diff --git a/ci/install-upstream-wheels.sh b/ci/install-upstream-wheels.sh
index 02d36259f82..f5cbaa0729b 100755
--- a/ci/install-upstream-wheels.sh
+++ b/ci/install-upstream-wheels.sh
@@ -53,7 +53,7 @@ python -m pip install \
     git+https://github.com/dask/dask \
     git+https://github.com/dask/dask-expr \
     git+https://github.com/dask/distributed \
-    git+https://github.com/zarr-developers/zarr-python \
+    git+https://github.com/zarr-developers/zarr-python.git@main \
     git+https://github.com/Unidata/cftime \
     git+https://github.com/pypa/packaging \
     git+https://github.com/hgrecco/pint \
diff --git a/pyproject.toml b/pyproject.toml
index 8cfbb6851b3..60d5a5f93a6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,9 +38,9 @@ complete = ["xarray[accel,etc,io,parallel,viz]"]
 io = [
   "netCDF4>=1.6.0",
   "h5netcdf",
-  "pydap",
   "scipy>=1.13",
-  "zarr>=2.18",
+  'pydap',
+  "zarr @ git+https://github.com/d-v-b/zarr-python.git@feat/fixed-length-strings",
   "fsspec",
   "cftime",
   "pooch",
diff --git a/xarray/backends/zarr.py b/xarray/backends/zarr.py
index 48405b906cd..cbe9855b8e0 100644
--- a/xarray/backends/zarr.py
+++ b/xarray/backends/zarr.py
@@ -36,7 +36,6 @@
 from xarray.core.variable import Variable
 from xarray.namedarray.parallelcompat import guess_chunkmanager
 from xarray.namedarray.pycompat import integer_types
-from xarray.namedarray.utils import module_available
 
 if TYPE_CHECKING:
     from xarray.backends.common import AbstractDataStore
@@ -106,7 +105,14 @@ def _choose_default_mode(
 
 
 def _zarr_v3() -> bool:
-    return module_available("zarr", minversion="3")
+    # don't use the module_available function because it doesn't report zarr v3 correctly.
+    try:
+        import zarr
+        from packaging.version import Version
+
+        return Version(zarr.__version__).major == 3
+    except ImportError:
+        return False
 
 
 # need some special secret attributes to tell us the dimensions
diff --git a/xarray/namedarray/utils.py b/xarray/namedarray/utils.py
index 96060730345..9e1e6e7cb7d 100644
--- a/xarray/namedarray/utils.py
+++ b/xarray/namedarray/utils.py
@@ -51,7 +51,6 @@ def module_available(module: str, minversion: str | None = None) -> bool:
     """
     if importlib.util.find_spec(module) is None:
         return False
-
     if minversion is not None:
         version = importlib.metadata.version(module)