diff --git a/idutils/detectors.py b/idutils/detectors.py
index fd6ec69..75d1f48 100644
--- a/idutils/detectors.py
+++ b/idutils/detectors.py
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2024 CERN.
+# SPDX-FileCopyrightText: 2026 University of Münster.
 # SPDX-License-Identifier: BSD-3-Clause
 #
 # In applying this license, CERN does not waive the privileges and immunities
@@ -52,6 +53,16 @@ def detect_identifier_schemes(val):
         for viaf_url in validators.viaf_urls:
             if val.startswith(viaf_url):
                 schemes.remove("handle")
+    if "isni" in schemes and "url" in schemes:
+        # check explicitly if it's an isni
+        for isni_url in validators.isni_urls:
+            if val.startswith(isni_url):
+                schemes.remove("url")
+    if "isni" in schemes and "handle" in schemes:
+        # check explicitly if it's an isni
+        for isni_url in validators.isni_urls:
+            if val.startswith(isni_url):
+                schemes.remove("handle")
 
     scheme_filter = IDUTILS_SCHEME_FILTER + custom_schemes_registry().pick_scheme_key(
         "filter"
diff --git a/idutils/utils.py b/idutils/utils.py
index dae49e1..1c78955 100644
--- a/idutils/utils.py
+++ b/idutils/utils.py
@@ -1,6 +1,7 @@
 # SPDX-FileCopyrightText: 2024 CERN.
 # SPDX-FileCopyrightText: 2023 abnf-to-regexp AUTHORS
 # SPDX-FileCopyrightText: 2025 Will Riley.
+# SPDX-FileCopyrightText: 2026 University of Münster.
 # SPDX-License-Identifier: BSD-3-Clause
 #
 # In applying this license, CERN does not waive the privileges and immunities
@@ -548,7 +549,7 @@ def _convert_x_to_10(x):
     "ISMR_EM",
 )
 """List of RRID authorities.
-    
+
 Manually collected from https://rrid.site/, so may not be complete
 """
 
@@ -556,3 +557,8 @@ def _convert_x_to_10(x):
     r"(?i)^(?:rrid:)?({codes})+_[A-Za-z0-9_-]+$".format(codes="|".join(RRID_CODES))
 )
 """Based on RRID example in the DataCite documentation"""
+
+isni_urls = (
+    "http://isni.org/isni/",
+    "https://isni.org/isni/",
+)
diff --git a/idutils/validators.py b/idutils/validators.py
index f8cf251..c04479a 100644
--- a/idutils/validators.py
+++ b/idutils/validators.py
@@ -1,5 +1,6 @@
 # SPDX-FileCopyrightText: 2024 CERN.
 # SPDX-FileCopyrightText: 2025 Will Riley.
+# SPDX-FileCopyrightText: 2026 University of Münster.
 # SPDX-License-Identifier: BSD-3-Clause
 #
 # In applying this license, CERN does not waive the privileges and immunities
@@ -102,6 +103,11 @@ def is_ean(val):
 
 def is_isni(val):
     """Test if argument is an International Standard Name Identifier."""
+    for isni_url in isni_urls:
+        if val.startswith(isni_url):
+            val = val[len(isni_url) :]
+            break
+
     val = val.replace("-", "").replace(" ", "").upper()
     if len(val) != 16:
         return False
@@ -121,6 +127,10 @@ def is_orcid(val):
     See http://support.orcid.org/knowledgebase/
         articles/116780-structure-of-the-orcid-identifier
     """
+    for isni_url in isni_urls:
+        if val.startswith(isni_url):
+            return False
+
     for orcid_url in orcid_urls:
         if val.startswith(orcid_url):
             val = val[len(orcid_url) :]
diff --git a/tests/test_idutils.py b/tests/test_idutils.py
index f67530b..176d78d 100644
--- a/tests/test_idutils.py
+++ b/tests/test_idutils.py
@@ -1,6 +1,7 @@
 # SPDX-FileCopyrightText: 2015-2022 CERN.
 # SPDX-FileCopyrightText: 2015-2018 Alan Rubin.
 # SPDX-FileCopyrightText: 2025 Will Riley.
+# SPDX-FileCopyrightText: 2026 University of Münster.
 # SPDX-License-Identifier: BSD-3-Clause
 #
 # In applying this license, CERN does not waive the privileges and immunities
@@ -310,6 +311,7 @@
         "http://orcid.org/0009-0002-4767-9017",
     ),
     ("1422-4586-3573-0476", ["isni"], "", ""),
+    ("https://isni.org/isni/1422-4586-3573-0476", ["isni"], "", ""),
     (
         "arXiv:1310.2590",
         [
@@ -1078,3 +1080,13 @@ def test_raid():
     assert "raid" in idutils.detect_identifier_schemes(
         "https://raid.org/10.83962/fb5be317"
     )
+
+
+def test_isni():
+    """Test ISNI validation."""
+    assert idutils.is_isni("1422-4586-3573-0476")
+    assert idutils.is_isni("http://isni.org/isni/1422-4586-3573-0476")
+    assert idutils.is_isni("https://isni.org/isni/1422-4586-3573-0476")
+    assert idutils.is_isni("0009-0005-6000-7479")
+    assert not idutils.is_isni("http://orcid.org/0009-0005-6000-7479")
+    assert not idutils.is_isni("https://orcid.org/0009-0005-6000-7479")