There is such a ticket.
Bodensee, or Lake Constance to give it its English name, is one of Europe's largest lakes. Generally speaking, the land to the north of the lake is in Germany while land to the south is in Switzerland. A short stretch of the lake's eastern shore is in Austria.The Tageskarte EURegio Bodensee is a ticket allowing a day's unlimited travel in the areas surrounding the lake, irrespective of country.
Several versions of the Tageskarte are available. The area of validity is split into three zones, with tickets available for one zone, two adjoining zones or all three.
Tageskarte Zone 1 (east) covers the eastern part of the lake and surrounding areas.
In Austria, validity extends over part of the Vorarlberg region, covering the towns of Bregenz, Dornbirn and Feldkirch.
Trains operated by ÖBB, Austrian state railways, accept the Tageskarte within this area.The Tageskarte can also be used on the local bus networks in the area.
The networks comprise "Landbus" interurban services...
...and local "Stadtbus" (town bus) networks such as here in Feldkirch.
On the north side of the lake, Zone 1 stretches into Germany.Within Germany, most of the area bordering Lake Constance is in Baden-Württemberg state. At the eastern end of the lake, however, the town of Lindau lies within Bavaria.
ÖBB trains cross the border to terminate at Lindau.
The Tageskarte EURegio Bodensee can be used in and around Lindau...
... on the local bus services within the town...
... on the regional bus services heading out of town...
...
and on local rail services heading westwards along the lake and
north-eastwards to nearby destinations.Some trains are operated by DBRegio (right), others by ALEX (below).
Within Germany, Tageskarte is not valid on inter-city trains
On the opposite shore of the lake, Zone 1 extends into Switzerland.
A variety of transport operators provide the transport network in this area.
Many of the rural and interurban bus services are provided by PostAuto. 
PostAuto use double-deck buses on some routes. In this scenic area, the views from the upper deck are particularly good.
A Tageskarte valid for Zone 1 can be used on bus services in this area irrespective of operator.
A couple of services operated by RegioBus enter Tageskarte's area of validity, in and around St Gallen.
The Tageskarte can also be used on Rheintal Bus (RTB) services, where these operate within the area.
Although illustrating Rheintal Bus, this image was taken in Buchs, outside the Tageskarte's area of validity.
The town of Rorschach, on the shore of the lake, has a small network of local bus routes. These operate under the "Seebus" name.
Some of the local train services are operated by SBB, Switzerland's national railway operator. Others are provided by private companies.
All accept Tageskarte within the relevant Zone.
Appenzeller Bahnen operate several lines in this area. These images show trains at Rorschach (below), and Heiden. These trains use a rack-and-pinion (or cogwheel) system where there are steep gradients.
The line from Rorschach to Heiden is standard gauge. Other lines operated by Appenzeller Bahnen are narrow-gauge.This one climbs out of the city of St Gallen, also using the rack-and-pinion system on steep gradients.
St Gallen has an extensive transport system, which I have covered in a previous post.A Tageskarte valid in Zone 1 can be used on St Gallen's bus network
St Gallen's bus system is one of two within the Tageskarte's area where trolleybuses operate.
I may be stretching it a little to claim that trams are one of the modes on which the Tageskarte EURegio Bodensee can be used. None of the towns or cities in the area of coverage have tram systems as such.
However, St Gallen used to have trams of its own. Although the city's tram system closed many years ago, some of the infrastructure remains in use.Trains on the "Trogenerbahn", operated by Appenzeller Bahnen, run on-street into the centre of St Gallen.
St Gallen is also home to a funicular lift. This is also covered by the Tageskarte EURegio Bodensee.
A ferry crosses the lake, linking the Swiss town of Romanshorn with Friedrichshafen in Germany.Both towns lie in an overlap between Zone 1 (east) and Zone 2 (central). A Tageskarte valid in either zone can be used on the ferry.
Another ferry links Meersburg, on the northern shore of the lake, with the city of Konstanz.
A Tageskarte valid for Zone 2 is valid on the ferry.
As well as foot passengers, bus passengers can also use a Zone 2 Tageskarte on routes which use the ferry.
Two interurban routes use the ferry to reach Konstanz from towns on and around the north shore of the lake.
There is a sizeable overlap between Zone 2 (central) and Zone 3 (west), covering parts of both Germany and Switzerland.
Many of the interurban and rural buses operating in this area wear DeutscheBahn liveries, either all-red or white and red.
Not all do, however.
The rail network also provides a number of interurban and regional links in this part of Germany. Local train services are provided by several companies.
DB Regio operate a number of routes.Double-deck trains operate a limited-stop inter-regional service from Konstanz to Karlsruhe. A Zone 2 Tageskarte is valid on this service as far Radolfzell, while a Zone 3 ticket can be used as far as Engen.
Local trains between Konstanz, Radolzell and Engen are operated as "Seehas".
Although the route is entirely within Germany, the trains are operated by a subsidiary of SBB, the Swiss national operator.
Hohenzollerische Landesbahn (HzL) operates the line from Radolfzell to Stockach.
Zone 3 only covers part of the route, but a Tageskarte valid for Zone 2 can be used throughout.
Local bus networks in a number of towns and cities feed into the interurban bus and rail services.These images were taken in Konstanz, which lies right on the border with Switzerland.
Route 908 from Konstanz crosses the border into Switzerland, providing a link to the neighbouring town of Kreuzlingen. This image was taken in Kreuzlingen.Both Konstanz and Kreuzlingen lie within the area where Zones 2 and 3 overlap.
Kreuzlingen has its own town bus network.
As in Zone 1, interurban and rural bus services in Zones 2 and 3 are generally provided by PostAuto, although there are some exceptions.
This image was taken at Kreuzlingen railway station where buses connect with local rail services.
During the evenings, PostAuto minibuses cross the border into Germany.Route 925 provides the bus link between Kreuzlingen and Konstanz at these times.
SBB train services also link Konstanz with Kreuzlingen, then head further south to Weinfelden. This image was taken at Konstanz."Thurbo" is the brand name used for a network of local train services in and around the Swiss canton of Thurgau. Most of Thurgau lies within the area covered by the Tageskarte (Zones 2 and/or 3), although the southern part of the canton is beyond the Tageskarte boundary.
Beyond the overlapping area of Zones 2 and 3, Zone 3 extends further west in both Germany and Switzerland, reaching the Swiss city of Schaffhausen.
Schaffhausen has trolleybuses, although the system comprises only one route.
The trolleybus route forms part of a network of local bus routes within Schaffhausen.
In the centre of Schaffhausen, the railway station forms an interchange hub between trains, city bus and trolleybus routes, and buses into the surrounding area.
Some of the bus services into the area surrounding Schaffhausen are provided by the Schaffhausen Bus network.
Others are provided by PostAuto.
Rheinfall ("Rhine Falls" in English) is one of Europe's largest waterfalls, on the river Rhine close to Schaffhausen. A railway line leaves Schaffhausen, then crosses the Rhine just above Rheinfall. A Tageskarte valid in Zone 3 can be used on this section of line.
So there it is. Tageskarte EURegio Bodensee can be used on buses, trolleybuses, tram-trains, trains, ferries and a funicular. Six modes, in parts of Austria, Germany and Switzerland. It is priced in both Euro and the Swiss Franc.
At the time of writing, a ticket valid in one zone is priced at €18, or 26CHF. A two-zone ticket costs €24 / 35CHF; a ticket valid across all three zones costs €31 / 45CHF. Group tickets, for up to 2 adults and up to 4 children travelling together, are also available for the same or less than the cost of two individual adult tickets.
I should point out that, while two of the ferries on the lake accept the Tageskarte, it is not valid on other boats which operate on the lake. Nevertheless, many of the excursion boats offer a 25% discount to holders of a valid Tageskarte. Discounts are also offered on two cable car systems in the Austrian part of Zone 1, as well as at several other visitor attractions across the areas covered by the Tageskarte.The Tageskarte EURegio Bodensee is not the only example of a day ticket valid in three countries. I have previously written about the euregioticket valid in the Dutch, German and Belgian border regions.
