diff --git a/data_structures/linked_list/has_loop.py b/data_structures/linked_list/has_loop.py
index a25204e3c4ce..10d9aa9893de 100644
--- a/data_structures/linked_list/has_loop.py
+++ b/data_structures/linked_list/has_loop.py
@@ -27,6 +27,9 @@ def __iter__(self) -> Iterator[Any]:
     def has_loop(self) -> bool:
         """
         A loop is when the exact same Node appears more than once in a linked list.
+        Uses Floyd's tortoise-and-hare cycle detection, so only constant
+        auxiliary space is used regardless of list length.
+        https://en.wikipedia.org/wiki/Cycle_detection#Floyd's_tortoise_and_hare
         >>> root_node = Node(1)
         >>> root_node.next_node = Node(2)
         >>> root_node.next_node.next_node = Node(3)
@@ -37,11 +40,14 @@ def has_loop(self) -> bool:
         >>> root_node.has_loop
         True
         """
-        try:
-            list(self)
-            return False
-        except ContainsLoopError:
-            return True
+        slow = self
+        fast = self
+        while fast is not None and fast.next_node is not None:
+            slow = slow.next_node if slow is not None else None
+            fast = fast.next_node.next_node
+            if slow is fast:
+                return True
+        return False
 
 
 if __name__ == "__main__":
@@ -61,3 +67,20 @@ def has_loop(self) -> bool:
 
     root_node = Node(1)
     print(root_node.has_loop)  # False
+
+    # Self-loop: a node points to itself
+    root_node = Node(1)
+    root_node.next_node = root_node
+    print(root_node.has_loop)  # True
+
+    # Loop involving the final node
+    root_node = Node(1)
+    root_node.next_node = Node(2)
+    root_node.next_node.next_node = Node(3)
+    root_node.next_node.next_node.next_node = root_node.next_node.next_node
+    print(root_node.has_loop)  # True
+
+    # Duplicate data values in different nodes must not be mistaken for a loop
+    root_node = Node(1)
+    root_node.next_node = Node(1)
+    print(root_node.has_loop)  # False