The rivers of Switzerland lead to three different seas: The
Rhein with its tributaries Aare and Thur drain 67.7% of the
water into the North Sea. The Rhone and the
Ticino (after the Lago Maggiore called Po) drain 18% into the
Mediterranean Sea. The Inn drains 4.4% into
the Black Sea
The major rivers:
| Name | Length within Switzerland | Catchment area | Source | Ends in or leaves Switzerland in |
| Rhein | 375 km | 27963 km² | Oberalp (Vorderrhein) & San Bernardino (Hinterrhein) | Leaves in Basel |
| Aare | 295 km | 17779 km² | Grimsel | Ends in Rhein near Koblenz, AG |
| Rhone | 264 km | 6947 km² | Grimsel | Leaves in Geneva |
| Inn | 104 km | 1792 km² | Maloja | Leaves in Vinadi (Engadin), GR |
| Thur | 125 km | 1724 km² | Toggenburg | Ends in Rhein near Ellikon, ZH |
| Ticino | 91 km | 1616 km² | Nufenen | Ends in Lago Maggiore, TI |