Konstanz: this is where your phone switches to the Swiss network fastest
Sites: BAKOM (retrieved 2026-10-07), map: © OpenStreetMap contributors. Straight line, not radio coverage. Within 10 km: Salt 26, Sunrise 12, Swisscom 24 sites (one site can carry several networks).
Why Konstanz is affected most
Konstanz and the Swiss town of Kreuzlingen merge into each other in the townscape. The map shows what that means for your phone: within 3 kilometres there are 19 Swiss sites, within 5 kilometres 31, within 10 kilometres 59. Your phone always picks the strongest network, and here that can be a Swiss one without you having crossed the border.
In July 2026 the Wochenblatt explicitly names Konstanz as an area where unexpected phone costs are a particular risk. As early as 2017, the Schwäbische Zeitung counted Konstanz among the places on the lake where phones easily connect to a foreign network.
What it can cost
According to the Consumer Advice Centre of Baden-Württemberg, calls in the Swiss network can cost almost three euros per minute, and in individual cases bills in the five-figure range are possible. Older reports named €1.49 per minute for a call to Germany and 23 cents and more per megabyte.
According to the Schwäbische Zeitung, a cost cap of €50 plus tax applies to mobile data abroad. How quickly you can get close to it is shown by the example on the home page: €47.60 in data charges shortly before the provider's price limit kicks in.
If you regularly go to Kreuzlingen
If you often travel to Switzerland from Konstanz, settings alone serve you badly: they also block the network you need there. A plan that includes Switzerland is worth it then. With Telekom (from MagentaMobil S) and fraenk it is included, with congstar it applies to data. An overview with sources is on the Plans page.
What helps in Konstanz
Konstanz in brief
Will I notice in Konstanz that I am on the Swiss network?
Not necessarily. Look at the status bar: if it says Swisscom, Sunrise or Salt, you are on the Swiss network. Some phones only show a brief message, and the bill arrives later.
Is it enough to switch off data roaming in Konstanz?
For mobile browsing, yes. Calls and SMS remain possible in the Swiss network and can cost money. If you want to rule that out, fix your network (option B in the instructions).
Sources
- Wochenblatt Reporter, 5 Jul 2026Consumer Advice Centre of Baden-Württemberg: almost three euros per minute for calls, in individual cases bills in the five-figure range; Konstanz named as a risk area. (German)
- Schwäbische Zeitung, 2017 (updated 2019)Friedrichshafen, Lindau and Konstanz named as places where phones easily connect to a foreign network; €1.49 per minute for calls to Germany, 23 cents and more per megabyte; cost cap of €50 plus tax for mobile data abroad. (German)
- BAKOM, mobile antenna sites (geo.admin.ch)Figures and distances on this page, retrieved 7 Oct 2026; straight line from the town centre, not radio coverage.