The 261km (162-mile) shoreline of Lake Constance is shared by three countries -- Switzerland, Germany, and Austria. The surrounding hills are covered with vineyards and orchards and are dotted with many farming villages. Vacationers are drawn here by the sunny, mild climate and nice beaches.

Lake Constance is divided into three parts, although the name is frequently applied to Bodensee, the largest part. At the western end of Bodensee, the lake splits into two branches: a long fjord called Überlingersee and an irregular marshland known as Untersee. Untersee is connected to the rest of the lake by a narrow channel of water, which is actually the young Rhine River. The blue felchen, a pikelike fish found only in Lake Constance, furnishes the district with a tasty and renowned specialty.

The Swiss gateway to Lake Constance is Rorschach, 11km (7 miles) northeast of St. Gallen. You can get here by train from Zurich in 1 1/2 hours (the train departs every hour) or from St. Gallen in 20 minutes. From Rorschach, you can continue on -- by frequent local trains or buses along the lake -- to the three major centers: Arbon, Horn, and Romanshorn. A well-organized network of modern passenger ferries links all these towns along the shore and connects Switzerland with Germany and Austria.

The Rorschach Tourist Office, Hauptstrasse 63 (tel. 071/841-70-34; www.tourist-rorschach.ch), provides an up-to-date timetable for all forms of transportation. Regular hours are Monday to Friday 8:30am to noon and 1:30 to 6pm. From May to September 15, the office is also open on Saturday 9am to 2pm; and in July and August Sunday 9am to 2pm. You can also contact one of the most popular boat lines, Schiffahrtsbetrieb Rorschach (tel. 071/466-78-88; www.schifffahrt-rorschach.ch), the best and most economical way to cruise from one town along the lake to another, thereby transforming a commuter trip into a cruise. This is easiest to do from May to September.

Your choice of towns along Lake Constance will depend almost entirely on your selection of a hotel. The towns and attractions are so similar that it is hard to tell where one town ends and another begins. All of them offer lakeside promenades and flower gardens overlooking the lake, and all of them can become centers for pleasure boating and trips on the lake. The towns are also so close together that even if you're in Romanshorn in the west, you can arrive at Rorschach in the east in minutes. Because it has a greater choice of hotels, we'd give the nod to Rorschach.

Once at Lake Constance, you'll find dozens of bike trails, each marked with a red sign, and each running around the southern tier (the Swiss side) of the lake.