diff --git a/docs/per-context-patches.md b/docs/per-context-patches.md
index 5f71c08..fc7c941 100644
--- a/docs/per-context-patches.md
+++ b/docs/per-context-patches.md
@@ -617,7 +617,7 @@ bundles are shipped in the wheel.
 | Audio seed | Derived from the identity (NewBrowser) or `randint(1, 2^32-1)` (NewContext) | Never 0 |
 | Timezone | From preset, or `timezone` in `CAMOU_CONFIG` | The init script calls `setTimezone()` only for an explicit value; otherwise the C++ side falls back to `CAMOU_CONFIG` (set from geoip at launch) or the browser default. |
 | Speech voices | `_generate_random_voice_subset()` | Follows the measured model in `voice-manifests.json`: Windows gets the display language's OneCore pack plus its legacy Desktop voices at their measured rate; macOS the compact + Eloquence base plus rare downloads; Linux speech-dispatcher's espeak-ng list. Seeded by the identity. NOT from presets. |
-| WebRTC IP | Not set by default | User sets via `window.setWebRTCIPv4()`. NewContext init script defaults to empty string `""` |
+| WebRTC IP | Not set by default | NewContext's `webrtc_ip` (or the proxy's exit IP) goes to `window.setWebRTCIPv4()` or `window.setWebRTCIPv6()` by address family; an invalid address raises `InvalidIP`. Without one, the init script calls `setWebRTCIPv4("")` |
 | Geolocation | User parameter or geoip detection | Via Playwright `context.setGeolocation()` |
 
 ### Key Files
diff --git a/pythonlib/camoufox/async_api.py b/pythonlib/camoufox/async_api.py
index e05c813..52cb498 100644
--- a/pythonlib/camoufox/async_api.py
+++ b/pythonlib/camoufox/async_api.py
@@ -204,7 +204,7 @@ async def AsyncNewContext(
         preset: A fingerprint preset dict to use. If None, fpgen draws a new identity.
         os: Target OS for the drawn identity ("windows", "macos", "linux").
         ff_version: Firefox major version to claim in the UA. Defaults to the browser's own.
-        webrtc_ip: IPv4 address to spoof for WebRTC ICE candidates.
+        webrtc_ip: IPv4 or IPv6 address to spoof for WebRTC ICE candidates.
         proxy: Per-context proxy (Playwright format: {"server": "...", "username": "...", "password": "..."}).
             Unless webrtc_ip and timezone_id are both given, they are looked up from the
             proxy's exit IP; InvalidIP is raised if that lookup fails.
diff --git a/pythonlib/camoufox/fingerprints.py b/pythonlib/camoufox/fingerprints.py
index 752076c..9e4ab16 100644
--- a/pythonlib/camoufox/fingerprints.py
+++ b/pythonlib/camoufox/fingerprints.py
@@ -11,6 +11,7 @@ from random import Random, choice, randint, randrange
 from typing import Any, Dict, FrozenSet, List, Optional, Set, Tuple
 
 from camoufox._warnings import FallbackWarning
+from camoufox.ip import valid_ipv4, validate_ip
 from camoufox.pkgman import load_yaml
 from camoufox.webgl import sample_webgl
 
@@ -1759,8 +1760,10 @@ def _build_init_script(values: Dict[str, Any]) -> str:
     # WebRTC IP
     ip = values.get('webrtcIP')
     if ip:
+        validate_ip(ip)
+        fn_name = 'setWebRTCIPv4' if valid_ipv4(ip) else 'setWebRTCIPv6'
         lines.append(
-            f'  if (typeof w.setWebRTCIPv4 === "function") w.setWebRTCIPv4({_json.dumps(ip)});'
+            f'  if (typeof w.{fn_name} === "function") w.{fn_name}({_json.dumps(ip)});'
         )
     else:
         lines.append(
diff --git a/pythonlib/camoufox/sync_api.py b/pythonlib/camoufox/sync_api.py
index be07644..5cd65d7 100644
--- a/pythonlib/camoufox/sync_api.py
+++ b/pythonlib/camoufox/sync_api.py
@@ -182,7 +182,7 @@ def NewContext(
         preset: A fingerprint preset dict to use. If None, fpgen draws a new identity.
         os: Target OS for the drawn identity ("windows", "macos", "linux").
         ff_version: Firefox major version to claim in the UA. Defaults to the browser's own.
-        webrtc_ip: IPv4 address to spoof for WebRTC ICE candidates.
+        webrtc_ip: IPv4 or IPv6 address to spoof for WebRTC ICE candidates.
         proxy: Per-context proxy (Playwright format: {"server": "...", "username": "...", "password": "..."}).
             Unless webrtc_ip and timezone_id are both given, they are looked up from the
             proxy's exit IP; InvalidIP is raised if that lookup fails.
diff --git a/pythonlib/tests/test_webrtc_ip_setter.py b/pythonlib/tests/test_webrtc_ip_setter.py
new file mode 100644
index 0000000..45dd224
--- /dev/null
+++ b/pythonlib/tests/test_webrtc_ip_setter.py
@@ -0,0 +1,23 @@
+"""The per-context init script hands a WebRTC IP to the setter for its family."""
+
+import pytest
+
+from camoufox.exceptions import InvalidIP
+from camoufox.fingerprints import _build_init_script
+
+
+def test_ipv4_goes_to_the_ipv4_setter():
+    script = _build_init_script({"webrtcIP": "203.0.113.7"})
+    assert 'w.setWebRTCIPv4("203.0.113.7")' in script
+    assert "setWebRTCIPv6(" not in script
+
+
+def test_ipv6_goes_to_the_ipv6_setter():
+    script = _build_init_script({"webrtcIP": "2001:db8::7"})
+    assert 'w.setWebRTCIPv6("2001:db8::7")' in script
+    assert "2001:db8::7" not in script.split("setWebRTCIPv6")[0]
+
+
+def test_an_invalid_address_is_refused():
+    with pytest.raises(InvalidIP):
+        _build_init_script({"webrtcIP": "not-an-ip"})