diff --git a/neo/rawio/cedrawio.py b/neo/rawio/cedrawio.py
index e53cc190d..59619767c 100644
--- a/neo/rawio/cedrawio.py
+++ b/neo/rawio/cedrawio.py
@@ -19,6 +19,10 @@
 Author : Samuel Garcia
 """
 
+import importlib
+import importlib.util
+from functools import cache
+
 import numpy as np
 
 from .baserawio import (
@@ -31,6 +35,33 @@
 )
 
 
+@cache
+def _get_sonpy_namespace():
+    """Return the sonpy namespace exposing SonFile, whatever the installed layout."""
+    if importlib.util.find_spec("sonpy") is None:
+        raise ImportError("sonpy is not installed. Install it with `pip install sonpy`.")
+
+    sonpy = importlib.import_module("sonpy")
+
+    # <= 1.9.5 binds the extension module as an attribute, not a submodule,
+    # so find_spec("sonpy.lib") cannot see it.
+    lib = getattr(sonpy, "lib", None)
+    if lib is not None and hasattr(lib, "SonFile"):
+        return lib
+
+    # >= 1.9.12 on Windows/macOS re-exports into the package namespace.
+    if hasattr(sonpy, "SonFile"):
+        return sonpy
+
+    # >= 1.9.12 on Linux ships an empty __init__.py.
+    if importlib.util.find_spec("sonpy.sonpy") is not None:
+        nested = importlib.import_module("sonpy.sonpy")
+        if hasattr(nested, "SonFile"):
+            return nested
+
+    raise ImportError("sonpy is installed but exposes no SonFile.")
+
+
 class CedRawIO(BaseRawIO):
     """
     Class for reading data from CED (Cambridge Electronic Design) spike2.
@@ -48,6 +79,13 @@ class CedRawIO(BaseRawIO):
 
     * This IO reads smr and smrx files
 
+    * sonpy is installed by the ``ced`` extra, but upstream only publishes wheels for Windows,
+      and for Linux and macOS from Python 3.14 onwards. Elsewhere the extra resolves to nothing
+      installable and this class raises an ImportError naming the constraint on first use; the
+      PyPI source distribution ships a Windows binary and is not usable.
+
+    * Old smr files can be read without sonpy using Spike2RawIO. Only smrx requires this class.
+
     """
 
     extensions = ["smr", "smrx"]
@@ -67,9 +105,9 @@ def _source_name(self):
         return self.filename
 
     def _parse_header(self):
-        import sonpy
+        sonpy_ns = _get_sonpy_namespace()
 
-        self.smrx_file = sonpy.lib.SonFile(sName=str(self.filename), bReadOnly=True)
+        self.smrx_file = sonpy_ns.SonFile(sName=str(self.filename), bReadOnly=True)
         smrx = self.smrx_file
 
         self._time_base = smrx.GetTimeBase()
@@ -82,7 +120,7 @@ def _parse_header(self):
         for chan_ind in range(smrx.MaxChannels()):
             chan_type = smrx.ChannelType(chan_ind)
             chan_id = str(chan_ind)
-            if chan_type == sonpy.lib.DataType.Adc:
+            if chan_type == sonpy_ns.DataType.Adc:
                 physical_chan = smrx.PhysicalChannel(chan_ind)
                 divide = smrx.ChannelDivide(chan_ind)
                 if self.take_ideal_sampling_rate:
@@ -105,13 +143,13 @@ def _parse_header(self):
                 buffer_id = ""
                 signal_channels.append((ch_name, chan_id, sr, dtype, units, gain, offset, stream_id, buffer_id))
 
-            elif chan_type == sonpy.lib.DataType.AdcMark:
+            elif chan_type == sonpy_ns.DataType.AdcMark:
                 # spike and waveforms : only spike times is used here
                 ch_name = smrx.GetChannelTitle(chan_ind)
                 first_time = smrx.FirstTime(chan_ind, 0, max_time)
                 max_time = smrx.ChannelMaxTime(chan_ind)
                 divide = smrx.ChannelDivide(chan_ind)
-                # here we don't use filter (sonpy.lib.MarkerFilter()) so we get all marker
+                # here we don't use filter (sonpy_ns.MarkerFilter()) so we get all marker
                 wave_marks = smrx.ReadWaveMarks(chan_ind, int(max_time / divide), 0, max_time)
 
                 # here we load in memory all spike once because the access is really slow
diff --git a/neo/test/iotest/test_cedio.py b/neo/test/iotest/test_cedio.py
index d47d45408..bbb956179 100644
--- a/neo/test/iotest/test_cedio.py
+++ b/neo/test/iotest/test_cedio.py
@@ -1,17 +1,10 @@
 import unittest
-from platform import system
-from sys import maxsize
 
 try:
-    if system() == "Windows":
-        if maxsize > 2**32:
-            import sonpy.amd64.sonpy
-        else:
-            import sonpy.win32.sonpy
-    elif system() == "Darwin":
-        import sonpy.darwin.sonpy
-    elif system() == "Linux":
-        import sonpy.linux.sonpy
+    from neo.rawio.cedrawio import _get_sonpy_namespace
+
+    # Raises ImportError if sonpy is missing or exposes no usable namespace.
+    _get_sonpy_namespace()
     from neo.io import CedIO
 except ImportError:
     HAVE_SONPY = False
diff --git a/neo/test/rawiotest/test_cedrawio.py b/neo/test/rawiotest/test_cedrawio.py
index f2dfde3b4..04923ed67 100644
--- a/neo/test/rawiotest/test_cedrawio.py
+++ b/neo/test/rawiotest/test_cedrawio.py
@@ -5,7 +5,10 @@
 from neo.test.rawiotest.common_rawio_test import BaseTestRawIO
 
 try:
-    import sonpy
+    from neo.rawio.cedrawio import _get_sonpy_namespace
+
+    # Raises ImportError if sonpy is missing or exposes no usable namespace.
+    _get_sonpy_namespace()
 
     HAVE_SONPY = True
 except ImportError:
diff --git a/pyproject.toml b/pyproject.toml
index d21d4181c..0cb04114e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -64,7 +64,7 @@ test = [
     "coverage",
     "coveralls",
     "pillow",
-    "sonpy;python_version<'3.10'",
+    "sonpy; platform_system=='Windows' or python_version>='3.14'",
     "pynwb",
     "probeinterface",
     "zugbruecke>=0.2",