Some trains continue from Rorschach to St. Margrethen, Bregenz (Vorarlberg, Austria) and Lindau (Bavaria, Germany) along the shores of Lake Constance (Bodensee).

[4] Thurbo, a joint venture of Swiss Federal Railways and the canton of Thurgau, operates the service.

The S7 operates half-hourly over the Lake line between Romanshorn and Rorschach.

Every other train operates over the Winterthur–Romanshorn line between Romanshorn and Weinfelden, stopping only at Amriswil.

[6] S7 (Weinfelden –) Romanshorn – Rorschach (– St. Margrethen – Bregenz – Lindau-Reutin – Lindau-Insel)[a] With the December 2021 timetable change, the Romanshorn–Rorschach trains were extended every two hours, on Saturdays and Sundays only, around the southern coast of Lake Constance to Bregenz and Lindau.