diff --git a/docs/changes/newsfragments/7978.breaking b/docs/changes/newsfragments/7978.breaking
new file mode 100644
index 000000000000..f91535e6f8c1
--- /dev/null
+++ b/docs/changes/newsfragments/7978.breaking
@@ -0,0 +1,14 @@
+A new ``resource`` parameter has been added that accepts an already-opened
+``pyvisa.resources.MessageBasedResource``, allowing a ``VisaInstrument`` to be
+constructed from an existing PyVISA resource handle. The ``resource`` parameter
+cannot be combined with ``address``, ``visalib`` or ``pyvisa_sim_file``. These arguments
+are only used to construct a new resource.
+
+The ``resource_manager``, ``visabackend`` and ``visalib`` ``visa_handle`` attributes of
+:class:`.VisaInstrument` have been converted to read-only properties.
+
+The ``_address`` property is deprecated in favour of ``address``.
+The ``visalib`` property is deprecated in favour of ``visabackend``.
+
+The method ``set_address`` now takes visalib as an argument. If this
+is not supplied the default visa library will be used.
diff --git a/pyproject.toml b/pyproject.toml
index a9745ddacc65..fb01f37cc98b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -35,7 +35,7 @@ dependencies = [
     "packaging>=20.0",
     "pandas>=1.5.0",
     "pyarrow>=11.0.0", # will become a requirement of pandas. Installing explicitly silences a warning
-    "pyvisa>=1.11.0, <1.17.0",
+    "pyvisa>=1.12.0, <1.17.0",
     "ruamel.yaml>=0.16.0,!=0.16.6",
     "tabulate>=0.9.0",
     "typing_extensions>=4.6.0",
diff --git a/src/qcodes/instrument/ip_to_visa.py b/src/qcodes/instrument/ip_to_visa.py
index 02245d8c448f..80d221341d48 100644
--- a/src/qcodes/instrument/ip_to_visa.py
+++ b/src/qcodes/instrument/ip_to_visa.py
@@ -24,7 +24,7 @@
 # Such a driver is just a two-line class definition.
 
 
-class IPToVisa(VisaInstrument, IPInstrument):  # type: ignore[misc]
+class IPToVisa(VisaInstrument, IPInstrument):  # type: ignore[override,misc]
     """
     Class to inject an VisaInstrument like behaviour in an
     IPInstrument that we'd like to use as a VISAInstrument with the
@@ -72,8 +72,7 @@ def __init__(
 
         traversable_handle = files("qcodes.instrument.sims") / pyvisa_sim_file
         with as_file(traversable_handle) as sim_visalib_path:
-            self.visalib = f"{sim_visalib_path!s}@sim"
-            self.set_address(address=address)
+            self.set_address(address=address, visalib=f"{sim_visalib_path!s}@sim")
 
         if device_clear:
             self.device_clear()
@@ -88,8 +87,10 @@ def close(self) -> None:
         if getattr(self, "visa_handle", None):
             self.visa_handle.close()
 
-        if getattr(self, "visabackend", None) == "sim" and getattr(
-            self, "resource_manager", None
+        if (
+            getattr(self, "visabackend", None) == "sim"
+            and getattr(self, "resource_manager", None)
+            and self.resource_manager is not None
         ):
             # The pyvisa-sim visalib has a session attribute but the resource manager is not generic in the
             # visalib type so we cannot get it in a type safe way
diff --git a/src/qcodes/instrument/sims/cryo_tm620.yaml b/src/qcodes/instrument/sims/cryo_tm620.yaml
index cb238bc848ac..5f1f50869120 100644
--- a/src/qcodes/instrument/sims/cryo_tm620.yaml
+++ b/src/qcodes/instrument/sims/cryo_tm620.yaml
@@ -24,5 +24,5 @@ devices:
 
 
 resources:
-  GPIB::1::INSTR:
+  GPIB0::1::INSTR:
     device: cryomag_tm620
diff --git a/src/qcodes/instrument/visa.py b/src/qcodes/instrument/visa.py
index 1556ab683274..66cdabd53ea9 100644
--- a/src/qcodes/instrument/visa.py
+++ b/src/qcodes/instrument/visa.py
@@ -12,10 +12,11 @@
 import pyvisa.constants as vi_const
 import pyvisa.resources
 from pyvisa.errors import InvalidSession
+from typing_extensions import deprecated
 
 import qcodes.validators as vals
 from qcodes.logger import get_instrument_logger
-from qcodes.utils import DelayedKeyboardInterrupt
+from qcodes.utils import DelayedKeyboardInterrupt, QCoDeSDeprecationWarning
 
 from .instrument import Instrument
 from .instrument_base import InstrumentBase, InstrumentBaseKWArgs
@@ -84,6 +85,14 @@ class VisaInstrumentKWArgs(TypedDict):
     """
     Name of a pyvisa-sim yaml file used to simulate the instrument.
     """
+    resource: NotRequired[pyvisa.resources.MessageBasedResource | None]
+    """
+    An already-opened :class:`pyvisa.resources.MessageBasedResource`.
+    When provided, the instrument wraps this resource instead of opening
+    a new connection. The instrument takes ownership and will close the
+    resource when the instrument is closed or garbage collected.
+    Mutually exclusive with ``address``, ``visalib`` and ``pyvisa_sim_file``.
+    """
 
 
 class VisaInstrument(Instrument):
@@ -93,6 +102,12 @@ class VisaInstrument(Instrument):
     Args:
         name: What this instrument is called locally.
         address: The visa resource name to use to connect.
+            Mutually exclusive with ``resource``.
+        resource: An already-opened :class:`pyvisa.resources.MessageBasedResource`.
+            When provided, the instrument wraps this resource instead of opening
+            a new connection. The instrument takes ownership and will close the
+            resource when the instrument is closed or garbage collected.
+            Mutually exclusive with ``address``, ``visalib`` and ``pyvisa_sim_file``.
         timeout: seconds to allow for responses.  If "unset" will read the value from
            `self.default_timeout`. None means wait forever. Default 5.
         terminator: Read and write termination character(s).
@@ -107,7 +122,7 @@ class VisaInstrument(Instrument):
             By default the IVI backend is used if found, but '@py' will use the
             ``pyvisa-py`` backend. Note that QCoDeS does not install (or even require)
             ANY backends, it is up to the user to do that. see eg:
-            http://pyvisa.readthedocs.org/en/stable/names.html
+            https://pyvisa.readthedocs.io/en/stable/introduction/names.html
         metadata: additional static metadata to add to this
             instrument's JSON snapshot.
         pyvisa_sim_file: Name of a pyvisa-sim yaml file used to simulate the instrument.
@@ -138,13 +153,14 @@ class VisaInstrument(Instrument):
     def __init__(
         self,
         name: str,
-        address: str,
+        address: str | None = None,
         timeout: float | None | Literal["Unset"] = "Unset",
         terminator: str | Literal["Unset"] | None = "Unset",  # noqa: PYI051
         # while unset is redundant here we add it to communicate to the user that unset has special meaning
         device_clear: bool = True,
         visalib: str | None = None,
         pyvisa_sim_file: str | None = None,
+        resource: pyvisa.resources.MessageBasedResource | None = None,
         **kwargs: Unpack[InstrumentBaseKWArgs],
     ):
         if terminator == "Unset":
@@ -163,12 +179,24 @@ def __init__(
             vals=vals.MultiType(vals.Numbers(min_value=0), vals.Enum(None)),
         )
 
-        if visalib is not None and pyvisa_sim_file is not None:
+        if resource is not None:
+            if address is not None:
+                raise TypeError("'address' and 'resource' are mutually exclusive")
+            if visalib is not None or pyvisa_sim_file is not None:
+                raise TypeError(
+                    "Cannot supply visalib or pyvisa_sim_file when using "
+                    "an existing resource"
+                )
+            visa_handle = resource
+            address = resource.resource_name
+        elif address is None:
+            raise TypeError("Either 'address' or 'resource' must be provided")
+        elif visalib is not None and pyvisa_sim_file is not None:
             raise RuntimeError(
                 "It's an error to supply both visalib and pyvisa_sim_file as "
                 "arguments to a VISA instrument"
             )
-        if pyvisa_sim_file is not None:
+        elif pyvisa_sim_file is not None:
             if ":" in pyvisa_sim_file:
                 module, pyvisa_sim_file = pyvisa_sim_file.split(":")
             else:
@@ -182,51 +210,99 @@ def __init__(
                         f"file {pyvisa_sim_file} from module: {module}"
                     )
                 visalib = f"{sim_visalib_path!s}@sim"
-                (
-                    visa_handle,
-                    visabackend,
-                    resource_manager,
-                ) = self._connect_and_handle_error(address, visalib)
+                visa_handle = self._connect_and_handle_error(address, visalib)
         else:
-            visa_handle, visabackend, resource_manager = self._connect_and_handle_error(
-                address, visalib
-            )
+            visa_handle = self._connect_and_handle_error(address, visalib)
         finalize(self, _close_visa_handle, visa_handle, str(self.name))
 
-        self.visabackend: str = visabackend
-        self.visa_handle: pyvisa.resources.MessageBasedResource = visa_handle
+        self._legacy_address = address
+
+        self._visa_handle: pyvisa.resources.MessageBasedResource = visa_handle
+
+        if device_clear:
+            self.device_clear()
+
+        self.set_terminator(terminator)
+        self.timeout.set(timeout)
+
+    @property
+    @deprecated(
+        "The _address property is deprecated, use the address property instead.",
+        category=QCoDeSDeprecationWarning,
+    )
+    def _address(self) -> str | None:
         """
-        The VISA resource used by this instrument.
+        DEPRECATED: USE self.address INSTEAD.
+        """
+        return self._legacy_address
+
+    @property
+    def address(self) -> str | None:
         """
-        self.resource_manager = resource_manager
+        The VISA resource name used to connect to this instrument.
+        Note that pyvisa normalizes the resource name when connecting,
+        so this may not be exactly the same as the address that was passed
+        in when creating the instrument.
+        """
+        return self.visa_handle.resource_name
+
+    @property
+    def resource_manager(self) -> pyvisa.ResourceManager | None:
         """
         The VISA resource manager used by this instrument.
         """
-        self.visalib: str | None = visalib
-        self._address = address
+        return self.visa_handle.visalib.resource_manager
 
-        if device_clear:
-            self.device_clear()
+    @property
+    def visa_handle(self) -> pyvisa.resources.MessageBasedResource:
+        """
+        The VISA resource used by this instrument.
+        """
+        return self._visa_handle
 
-        self.set_terminator(terminator)
-        self.timeout.set(timeout)
+    @property
+    def visabackend(self) -> str:
+        """
+        The VISA backend used by this instrument.
+        """
+        class_name = self.visa_handle.visalib.__class__.__name__
+        if class_name == "SimVisaLibrary":
+            return "sim"
+        elif class_name == "IVIVisaLibrary":
+            return "ivi"
+        elif class_name == "PyVisaLibrary":
+            return "py"
+        else:
+            self.visa_log.info(
+                f"Could not determine VISA backend from visa library class name: {class_name} falling back to IVI default."
+            )
+            return "ivi"
+
+    @property
+    @deprecated(
+        "The visalib property is deprecated, use the visabackend property instead.",
+        category=QCoDeSDeprecationWarning,
+    )
+    def visalib(self) -> str | None:
+        """
+        The VISA library used by this instrument.
+        """
+        return f"{self.visa_handle.visalib.library_path}@{self.visabackend}"
 
     def _connect_and_handle_error(
         self, address: str, visalib: str | None
-    ) -> tuple[pyvisa.resources.MessageBasedResource, str, pyvisa.ResourceManager]:
+    ) -> pyvisa.resources.MessageBasedResource:
         try:
-            visa_handle, visabackend, resource_manager = self._open_resource(
-                address, visalib
-            )
+            visa_handle = self._open_resource(address, visalib)
         except Exception as e:
             self.visa_log.exception(f"Could not connect at {address}")
             self.close()
             raise e
-        return visa_handle, visabackend, resource_manager
+        return visa_handle
 
     def _open_resource(
         self, address: str, visalib: str | None
-    ) -> tuple[pyvisa.resources.MessageBasedResource, str, pyvisa.ResourceManager]:
+    ) -> pyvisa.resources.MessageBasedResource:
         # in case we're changing the address - close the old handle first
         if getattr(self, "visa_handle", None):
             self.visa_handle.close()
@@ -236,11 +312,9 @@ def _open_resource(
                 f"Opening PyVISA Resource Manager with visalib: {visalib}"
             )
             resource_manager = pyvisa.ResourceManager(visalib)
-            visabackend = visalib.split("@")[1]
         else:
             self.visa_log.info("Opening PyVISA Resource Manager with default backend.")
             resource_manager = pyvisa.ResourceManager()
-            visabackend = "ivi"
 
         self.visa_log.info(f"Opening PyVISA resource at address: {address}")
         resource = resource_manager.open_resource(address)
@@ -248,26 +322,28 @@ def _open_resource(
             resource.close()
             raise TypeError("QCoDeS only support MessageBasedResource Visa resources")
 
-        return resource, visabackend, resource_manager
+        return resource
 
-    def set_address(self, address: str) -> None:
+    def set_address(
+        self,
+        address: str,
+        visalib: str | None,
+    ) -> None:
         """
-        Set the address for this instrument.
+        Set the address for this instrument. Note in most cases
+        this method is not recommended and it is better to close the instrument and
+        create a new instance of the instrument with the new address.
 
         Args:
             address: The visa resource name to use to connect. The address
                 should be the actual address and just that. If you wish to
-                change the backend for VISA, use the self.visalib attribute
-                (and then call this function).
+                change the backend for VISA, use the visalib argument
+            visalib: Visa backend to use when connecting to this instrument.
+                If not supplied use the default backend.
 
         """
-        resource, visabackend, resource_manager = self._open_resource(
-            address, self.visalib
-        )
-        self.visa_handle = resource
-        self._address = address
-        self.visabackend = visabackend
-        self.resource_manager = resource_manager
+        self._visa_handle = self._open_resource(address, visalib)
+        self._legacy_address = address
 
     def device_clear(self) -> None:
         """Clear the buffers of the device"""
@@ -328,12 +404,17 @@ def close(self) -> None:
         if getattr(self, "visa_handle", None):
             self.visa_handle.close()
 
-        if getattr(self, "visabackend", None) == "sim" and getattr(
-            self, "resource_manager", None
+        if (
+            getattr(self, "visabackend", None) == "sim"
+            and getattr(self, "resource_manager", None)
+            and self.resource_manager is not None
         ):
             # The pyvisa-sim visalib has a session attribute but the resource manager is not generic in the
             # visalib type so we cannot get it in a type safe way
-            known_sessions = getattr(self.resource_manager.visalib, "sessions", ())
+
+            known_sessions: tuple[int, ...] = getattr(
+                self.resource_manager.visalib, "sessions", ()
+            )
 
             try:
                 this_session = self.resource_manager.session
@@ -425,7 +506,7 @@ def snapshot_base(
             update=update, params_to_skip_update=params_to_skip_update
         )
 
-        snap["address"] = self._address
+        snap["address"] = self.address
         snap["terminator"] = self.visa_handle.read_termination
         snap["read_terminator"] = self.visa_handle.read_termination
         snap["write_terminator"] = self.visa_handle.write_termination
diff --git a/src/qcodes/instrument_drivers/Keysight/Infiniium.py b/src/qcodes/instrument_drivers/Keysight/Infiniium.py
index 9c579b00d370..e411beed9cff 100644
--- a/src/qcodes/instrument_drivers/Keysight/Infiniium.py
+++ b/src/qcodes/instrument_drivers/Keysight/Infiniium.py
@@ -887,10 +887,7 @@ def __init__(
 
         # Check if we are using pyvisa-py as our visa lib and warn users that
         # this may cause long digitize operations to fail
-        if (
-            self.visa_handle.visalib.library_path == "py"
-            and not silence_pyvisapy_warning
-        ):
+        if self.visabackend == "py" and not silence_pyvisapy_warning:
             self.log.warning(
                 "Timeout not handled correctly in pyvisa_py. This may cause"
                 " long acquisitions to fail. Either use ni/keysight visalib"
diff --git a/src/qcodes/instrument_drivers/QDev/QDac_channels.py b/src/qcodes/instrument_drivers/QDev/QDac_channels.py
index d7ec6e79e141..7d0a8fd0dd4f 100644
--- a/src/qcodes/instrument_drivers/QDev/QDac_channels.py
+++ b/src/qcodes/instrument_drivers/QDev/QDac_channels.py
@@ -762,7 +762,7 @@ def connect_message(
         """
         self.visa_handle.write("status")
 
-        log.info(f"Connected to QDac on {self._address}, {self.visa_handle.read()}")
+        log.info(f"Connected to QDac on {self.address}, {self.visa_handle.read()}")
 
         # take care of the rest of the output
         for _ in range(self._output_n_lines):
diff --git a/src/qcodes/instrument_drivers/tektronix/AWG5014.py b/src/qcodes/instrument_drivers/tektronix/AWG5014.py
index 23cb84ed93dd..5907bff2730b 100644
--- a/src/qcodes/instrument_drivers/tektronix/AWG5014.py
+++ b/src/qcodes/instrument_drivers/tektronix/AWG5014.py
@@ -175,7 +175,6 @@ def __init__(
         """
         super().__init__(name, address, **kwargs)
 
-        self._address = address
         self.num_channels = num_channels
 
         self._values: dict[str, dict[str, dict[str, npt.NDArray | float | None]]] = {}
diff --git a/tests/drivers/test_CopperMountain_M5065.py b/tests/drivers/test_CopperMountain_M5065.py
index 27cd161aba06..cbd6d3b24a9a 100644
--- a/tests/drivers/test_CopperMountain_M5065.py
+++ b/tests/drivers/test_CopperMountain_M5065.py
@@ -25,7 +25,7 @@ def vna():
 
 def test_m5065_instantiation(vna):
     assert vna.name == "M5065"
-    assert vna._address == "TCPIP0::localhost::hislip0::INSTR"
+    assert vna.address == "TCPIP0::localhost::hislip0::INSTR"
 
 
 def test_idn_command(vna):
diff --git a/tests/drivers/test_CopperMountain_M5180.py b/tests/drivers/test_CopperMountain_M5180.py
index dc011e347e9e..84a55af31074 100644
--- a/tests/drivers/test_CopperMountain_M5180.py
+++ b/tests/drivers/test_CopperMountain_M5180.py
@@ -25,7 +25,7 @@ def vna():
 
 def test_m5180_instantiation(vna):
     assert vna.name == "M5180"
-    assert vna._address == "TCPIP0::localhost::hislip0::INSTR"
+    assert vna.address == "TCPIP0::localhost::hislip0::INSTR"
 
 
 def test_idn_command(vna):
diff --git a/tests/drivers/test_cryomagnetics_4g.py b/tests/drivers/test_cryomagnetics_4g.py
index 0dbf37bb725f..ac9943cf6d48 100644
--- a/tests/drivers/test_cryomagnetics_4g.py
+++ b/tests/drivers/test_cryomagnetics_4g.py
@@ -32,8 +32,10 @@ def fixture_cryo_instrument() -> "Generator[CryomagneticsModel4G,None,None]":
 
 def test_initialization(cryo_instrument: CryomagneticsModel4G) -> None:
     assert cryo_instrument.name == "test_cryo_4g"
-    assert cryo_instrument._address == "GPIB::1::INSTR"
-    # assert cryo_instrument.terminator == "\n"
+    assert cryo_instrument.address == "GPIB0::1::INSTR"
+    # the address is normalized by pyvisa meaning that in this case an extra 0 is added after GPIB.
+    assert cryo_instrument.visa_handle.write_termination == "\n"
+    assert cryo_instrument.visa_handle.read_termination == "\n"
 
 
 def test_get_field(cryo_instrument: CryomagneticsModel4G) -> None:
@@ -45,7 +47,8 @@ def test_get_field(cryo_instrument: CryomagneticsModel4G) -> None:
 def test_initialization_visa_sim(cryo_instrument: CryomagneticsModel4G) -> None:
     # Test to ensure correct initialization of the CryomagneticsModel4G instrument
     assert cryo_instrument.name == "test_cryo_4g"
-    assert cryo_instrument._address == "GPIB::1::INSTR"
+    assert cryo_instrument.address == "GPIB0::1::INSTR"
+    # the address is normalized by pyvisa meaning that in this case an extra 0 is added after GPIB.
 
 
 @pytest.mark.parametrize(
diff --git a/tests/drivers/test_cryomagnetics_TM620.py b/tests/drivers/test_cryomagnetics_TM620.py
index 79cbf404ec1b..294f69ba4568 100644
--- a/tests/drivers/test_cryomagnetics_TM620.py
+++ b/tests/drivers/test_cryomagnetics_TM620.py
@@ -1,18 +1,22 @@
+from typing import TYPE_CHECKING
 from unittest.mock import patch
 
 import pytest
 
 from qcodes.instrument_drivers.cryomagnetics import CryomagneticsModelTM620
 
+if TYPE_CHECKING:
+    from collections.abc import Generator
+
 
 @pytest.fixture(name="tm620", scope="function")
-def fixture_tm620():
+def fixture_tm620() -> "Generator[CryomagneticsModelTM620, None, None]":
     """
     Fixture to create and yield a CryomagneticsModelTM620 object and close it after testing.
     """
     instrument = CryomagneticsModelTM620(
         name="test_cryo_tm620",
-        address="GPIB::2::INSTR",
+        address="GPIB0::1::INSTR",
         terminator="\r\n",
         pyvisa_sim_file="cryo_tm620.yaml",
     )
@@ -22,7 +26,7 @@ def fixture_tm620():
 
 def test_initialization(tm620):
     assert tm620.name == "test_cryo_tm620"
-    assert tm620._address == "GPIB::2::INSTR"
+    assert tm620.address == "GPIB0::1::INSTR"
     assert hasattr(tm620, "shield")
     assert hasattr(tm620, "magnet")
 
diff --git a/tests/drivers/test_lakeshore_372.py b/tests/drivers/test_lakeshore_372.py
index 4ebe96f40f49..e88dbbb95979 100644
--- a/tests/drivers/test_lakeshore_372.py
+++ b/tests/drivers/test_lakeshore_372.py
@@ -55,7 +55,7 @@ def __init__(self, *args, **kwargs) -> None:
         # cycle through all methods
         for func_name in func_names:
             with warnings.catch_warnings():
-                if func_name == "_name":
+                if func_name in {"_name", "_address", "visalib"}:
                     # silence warning when getting deprecated attribute
                     warnings.simplefilter("ignore", category=QCoDeSDeprecationWarning)
 
diff --git a/tests/test_visa.py b/tests/test_visa.py
index 86e2869cecc3..f18ad4d08520 100644
--- a/tests/test_visa.py
+++ b/tests/test_visa.py
@@ -13,6 +13,7 @@
 from qcodes.instrument import Instrument, VisaInstrument
 from qcodes.instrument_drivers.AimTTi import AimTTiPL601
 from qcodes.instrument_drivers.american_magnetics import AMIModel430
+from qcodes.utils import QCoDeSDeprecationWarning
 from qcodes.validators import Numbers
 
 
@@ -29,10 +30,14 @@ def __init__(self, *args, **kwargs):
 
     def _open_resource(
         self, address: str, visalib: str | None
-    ) -> tuple[pyvisa.resources.MessageBasedResource, str, pyvisa.ResourceManager]:
+    ) -> pyvisa.resources.MessageBasedResource:
         if visalib is None:
             visalib = "MockVisaLib"
-        return MockVisaHandle(), visalib, pyvisa.ResourceManager("@sim")
+        return MockVisaHandle()
+
+    @property
+    def visabackend(self) -> str:
+        return "sim"
 
 
 class MockVisaHandle(pyvisa.resources.MessageBasedResource):
@@ -47,6 +52,8 @@ class MockVisaHandle(pyvisa.resources.MessageBasedResource):
     - a state > 10 throws an error
     """
 
+    resource_name: str = "MOCK::INSTR"  # pyright: ignore[reportIncompatibleVariableOverride]
+
     def __init__(self):
         self.state = 0
         self.closed = False
@@ -132,6 +139,7 @@ def use_magnet() -> pyvisa.ResourceManager:
             terminator="\n",
         )
         assert list(Instrument._all_instruments.keys()) == ["x"]
+        assert x.resource_manager is not None
         assert len(x.resource_manager.list_opened_resources()) == 1
         assert x.resource_manager.list_opened_resources() == [x.visa_handle]
         return x.resource_manager
@@ -190,7 +198,11 @@ def test_visa_backend(mocker, request: FixtureRequest) -> None:
     address_opened = [None]
 
     class MockBackendVisaInstrument(VisaInstrument):
-        visa_handle = MockVisaHandle()
+        _visa_handle = MockVisaHandle()
+
+        @property
+        def visabackend(self) -> str:
+            return "sim"
 
     class MockRM:
         def open_resource(self, address):
@@ -249,8 +261,19 @@ def test_load_pyvisa_sim_file_implict_module(request: FixtureRequest) -> None:
     )
     request.addfinalizer(driver.close)
     assert driver.visabackend == "sim"
-    assert driver.visalib is not None
-    path_str, backend = driver.visalib.split("@")
+
+    assert Path(driver.visa_handle.visalib.library_path).match(
+        "qcodes/instrument/sims/AimTTi_PL601P.yaml"
+    )
+    assert driver.visa_handle.visalib.__class__.__name__ == "SimVisaLibrary"
+
+    # legacy
+    with pytest.warns(
+        QCoDeSDeprecationWarning, match="The visalib property is deprecated"
+    ):
+        visalib = driver.visalib  # pyright: ignore[reportDeprecated]
+    assert visalib is not None
+    path_str, backend = visalib.split("@")
     assert backend == "sim"
     path = Path(path_str)
     assert path.match("qcodes/instrument/sims/AimTTi_PL601P.yaml")
@@ -264,8 +287,17 @@ def test_load_pyvisa_sim_file_explicit_module(request: FixtureRequest) -> None:
     )
     request.addfinalizer(driver.close)
     assert driver.visabackend == "sim"
-    assert driver.visalib is not None
-    path_str, backend = driver.visalib.split("@")
+    assert Path(driver.visa_handle.visalib.library_path).match(
+        "qcodes/instrument/sims/AimTTi_PL601P.yaml"
+    )
+    assert driver.visa_handle.visalib.__class__.__name__ == "SimVisaLibrary"
+
+    with pytest.warns(
+        QCoDeSDeprecationWarning, match="The visalib property is deprecated"
+    ):
+        visalib = driver.visalib  # pyright: ignore[reportDeprecated]
+    assert visalib is not None
+    path_str, backend = visalib.split("@")
     assert backend == "sim"
     path = Path(path_str)
     assert path.match("qcodes/instrument/sims/AimTTi_PL601P.yaml")
@@ -295,3 +327,52 @@ def test_load_pyvisa_sim_file_invalid_module_raises(request: FixtureRequest) ->
             address="GPIB::1::INSTR",
             pyvisa_sim_file="qcodes.instrument.not_a_module:AimTTi_PL601P.yaml",
         )
+
+
+def test_existing_resource(request: FixtureRequest) -> None:
+    handle = MockVisaHandle()
+    mv = MockVisa("from_resource", resource=handle)
+    request.addfinalizer(mv.close)
+    assert mv.visa_handle is handle
+    assert mv.address == "MOCK::INSTR"
+    mv.state.set(5)
+    assert mv.state.get() == 5
+
+
+def test_existing_resource_with_address_raises() -> None:
+    handle = MockVisaHandle()
+    with pytest.raises(
+        TypeError,
+        match=re.escape("'address' and 'resource' are mutually exclusive"),
+    ):
+        MockVisa("bad", address="some_address", resource=handle)
+
+
+def test_existing_resource_with_visalib_raises() -> None:
+    handle = MockVisaHandle()
+    with pytest.raises(
+        TypeError,
+        match=re.escape(
+            "Cannot supply visalib or pyvisa_sim_file when using an existing resource"
+        ),
+    ):
+        MockVisa("bad", resource=handle, visalib="@py")
+
+
+def test_existing_resource_with_pyvisa_sim_file_raises() -> None:
+    handle = MockVisaHandle()
+    with pytest.raises(
+        TypeError,
+        match=re.escape(
+            "Cannot supply visalib or pyvisa_sim_file when using an existing resource"
+        ),
+    ):
+        MockVisa("bad", resource=handle, pyvisa_sim_file="somefile.yaml")
+
+
+def test_no_address_or_resource_raises() -> None:
+    with pytest.raises(
+        TypeError,
+        match=re.escape("Either 'address' or 'resource' must be provided"),
+    ):
+        MockVisa("bad")