diff --git a/tests/routes/test_collections.py b/tests/routes/test_collections.py
index 4ce3cf3..65fdd06 100644
--- a/tests/routes/test_collections.py
+++ b/tests/routes/test_collections.py
@@ -372,3 +372,20 @@ def test_collections_temporal_extent_datetime_column(app):
     assert len(intervals) == 4
     assert intervals[0][0] == "2004-10-19T10:23:54+00:00"
     assert intervals[0][1] == "2007-10-24T00:00:00+00:00"
+
+def test_collections_collectionId_substring_filter(app):
+    """Test /collections endpoint."""
+    response = app.get("/collections", params={"collectionId_substring": "_mgrs"})
+    assert response.status_code == 200
+    assert response.headers["content-type"] == "application/json"
+    body = response.json()
+
+    ids = [x["id"] for x in body["collections"]]
+
+    assert "public.sentinel_mgrs" in ids
+    assert "pg_temp.landsat_centroids" not in ids
+    assert "pg_temp.hexagons" not in ids
+    assert "pg_temp.squares" not in ids
+    assert "public.st_squaregrid" not in ids
+    assert "public.st_hexagongrid" not in ids
+    assert "public.st_subdivide" not in ids
diff --git a/tipg/dependencies.py b/tipg/dependencies.py
index a82feeb..58b543e 100644
--- a/tipg/dependencies.py
+++ b/tipg/dependencies.py
@@ -233,6 +233,21 @@ def datetime_query(
 
     return None
 
+def collectionId_substring_query(
+    collectionId_substring: Annotated[Optional[str], Query(description="Filter based on collectionId substring regex.")] = None
+) -> Optional[str]:
+    """collectionId substring dependency."""
+    compiled_substring = None
+    if collectionId_substring:
+        try:
+            # Attempt to compile the substring pattern provided by the user
+            compiled_substring = re.compile(collectionId_substring)
+        except re.error as e:
+            raise HTTPException(
+                status_code=422,
+                detail=f"Invalid substring '{collectionId_substring}' provided for 'collectionId_substring': {e}"
+            )
+    return compiled_substring
 
 def properties_query(
     properties: Annotated[
@@ -450,6 +465,7 @@ def CollectionsParams(
             description="Starts the response at an offset.",
         ),
     ] = None,
+    collectionId_substring: Annotated[Optional[str], Depends(collectionId_substring_query)] = None
 ) -> CollectionList:
     """Return Collections Catalog."""
     limit = limit or 0
@@ -487,6 +503,15 @@ def CollectionsParams(
             and t_intersects(datetime_filter, collection.dt_bounds)
         ]
 
+    # collectionId substring filter
+    if collectionId_substring is not None:
+        collections_list = [
+            collection
+            for collection in collections_list
+            # Use search() to find the substring anywhere in the collection ID
+            if collectionId_substring.search(collection.id)
+        ]
+
     matched = len(collections_list)
 
     if limit: