diff --git a/python/tests/test_collection.py b/python/tests/test_collection.py
index b03d1e3cf..49fa91550 100644
--- a/python/tests/test_collection.py
+++ b/python/tests/test_collection.py
@@ -426,6 +426,26 @@ def test_collection_optimize(self, test_collection: Collection):
 # ----------------------------
 @pytest.mark.usefixtures("test_collection")
 class TestCollectionFetch:
+    @pytest.mark.parametrize("ids", [None, 1, b"doc_1", "", ["doc_1", None], [""]])
+    def test_collection_fetch_rejects_invalid_ids(self, ids):
+        collection = Collection.__new__(Collection)
+        collection._obj = MagicMock()
+
+        with pytest.raises(ValueError, match="ids must"):
+            collection.fetch(ids)
+
+        collection._obj.Fetch.assert_not_called()
+
+    def test_collection_fetch_accepts_tuple_ids(self):
+        collection = Collection.__new__(Collection)
+        collection._obj = MagicMock()
+        collection._obj.Fetch.return_value = {}
+
+        result = collection.fetch(("doc_1", "doc_2"))
+
+        assert result == {}
+        collection._obj.Fetch.assert_called_once_with(["doc_1", "doc_2"], None, True)
+
     def test_collection_fetch(
         self, collection_with_single_doc: Collection, single_doc: Doc
     ):
@@ -807,6 +827,26 @@ def test_collection_upsert_batch(
 # ----------------------------
 @pytest.mark.usefixtures("test_collection")
 class TestCollectionDelete:
+    @pytest.mark.parametrize("ids", [None, 1, b"doc_1", "", ["doc_1", None], [""]])
+    def test_collection_delete_rejects_invalid_ids(self, ids):
+        collection = Collection.__new__(Collection)
+        collection._obj = MagicMock()
+
+        with pytest.raises(ValueError, match="ids must"):
+            collection.delete(ids)
+
+        collection._obj.Delete.assert_not_called()
+
+    def test_collection_delete_accepts_tuple_ids(self):
+        collection = Collection.__new__(Collection)
+        collection._obj = MagicMock()
+        collection._obj.Delete.return_value = ["ok_1", "ok_2"]
+
+        result = collection.delete(("doc_1", "doc_2"))
+
+        assert result == ["ok_1", "ok_2"]
+        collection._obj.Delete.assert_called_once_with(["doc_1", "doc_2"])
+
     def test_empty_collection_delete(self, test_collection: Collection, single_doc):
         result = test_collection.delete(single_doc.id)
         assert bool(result)
diff --git a/python/zvec/model/collection.py b/python/zvec/model/collection.py
index a002d0de5..2dff1c613 100644
--- a/python/zvec/model/collection.py
+++ b/python/zvec/model/collection.py
@@ -14,6 +14,7 @@
 from __future__ import annotations
 
 import warnings
+from collections.abc import Sequence
 from typing import Optional, Union, overload
 
 from zvec._zvec import _Collection
@@ -48,6 +49,24 @@ def _require_positive_integer(value, name: str) -> None:
         raise ValueError(f"{name} must be a positive integer")
 
 
+DocIds = Union[str, list[str], tuple[str, ...]]
+
+
+def _normalize_doc_ids(ids: DocIds) -> tuple[list[str], bool]:
+    if isinstance(ids, str):
+        if not ids:
+            raise ValueError("ids must contain non-empty strings")
+        return [ids], True
+
+    if not isinstance(ids, Sequence) or isinstance(ids, (bytes, bytearray)):
+        raise ValueError("ids must be a string or a sequence of strings")
+
+    id_list = ids if isinstance(ids, list) else list(ids)
+    if any(not isinstance(doc_id, str) or not doc_id for doc_id in id_list):
+        raise ValueError("ids must contain non-empty strings")
+    return id_list, False
+
+
 class Collection:
     """Represents an opened collection in Zvec.
 
@@ -324,21 +343,20 @@ def delete(self, ids: str) -> Status:
         pass
 
     @overload
-    def delete(self, ids: list[str]) -> list[Status]:
+    def delete(self, ids: Union[list[str], tuple[str, ...]]) -> list[Status]:
         pass
 
-    def delete(self, ids: Union[str, list[str]]) -> Union[Status, list[Status]]:
+    def delete(self, ids: DocIds) -> Union[Status, list[Status]]:
         """Delete documents by ID.
 
         Args:
-            ids (Union[str, list[str]]): One or more document IDs to delete.
+            ids (Union[str, list[str], tuple[str, ...]]): One or more document IDs to delete.
 
         Returns:
             Union[Status, list[Status]]: If a single id was given, returns its Status;
             if a list was given, returns a list of Status objects.
         """
-        is_single = isinstance(ids, str)
-        id_list = [ids] if isinstance(ids, str) else ids
+        id_list, is_single = _normalize_doc_ids(ids)
         results = self._obj.Delete(id_list)
         return results[0] if is_single else results
 
@@ -353,7 +371,7 @@ def delete_by_filter(self, filter: str) -> None:
     # ========== Collection DQL-fetch Methods ==========
     def fetch(
         self,
-        ids: Union[str, list[str]],
+        ids: DocIds,
         *,
         output_fields: Optional[list[str]] = None,
         include_vector: bool = True,
@@ -361,7 +379,7 @@ def fetch(
         """Retrieve documents by ID.
 
         Args:
-            ids (Union[str, list[str]]): Document IDs to fetch.
+            ids (Union[str, list[str], tuple[str, ...]]): Document IDs to fetch.
             output_fields (Optional[list[str]], optional): Scalar fields to
                 include. If None, all fields are returned. Defaults to None.
             include_vector (bool, optional): Whether to include vector data in
@@ -370,8 +388,8 @@ def fetch(
         Returns:
             dict[str, Doc]: Mapping from ID to document. Missing IDs are omitted.
         """
-        ids = [ids] if isinstance(ids, str) else ids
-        docs = self._obj.Fetch(ids, output_fields, include_vector)
+        id_list, _ = _normalize_doc_ids(ids)
+        docs = self._obj.Fetch(id_list, output_fields, include_vector)
         return {
             doc_id: py_doc
             for doc_id, core_doc in docs.items()