Tümlau Bay (German: Tümlauer Bucht) is a bay on the west coast of the Eiderstedt peninsula in Germany. It is the last large bay on the North Frisian coast that has not been fully dyked off.[1] The southern part of the bay lies in the municipality of Tümlauer-Koog; the northern shore is part of Westerhever. A prominent landmark on the bay is the Westerheversand Lighthouse.
On the dyke around Tümlau Bay runs a cycle path which is signposted Exkurs Westerhever Leuchtturm ("Westerhever Lighthouse Excursion"). It is part of the North Sea Cycle Route (Nordseeküsten-Radweg).