The lake was formed as a glacial basin during the Würm glaciation period.
It is the largest lake in the Nagelfluhkette Nature Park, which is the first German-Austrian cross-border nature park.
The lake is fed by several smaller streams, including the Aubach, and drains via the Konstanzer Ach.
The water temperature in mid-summer typically reaches between 18 and 22 degrees Celsius.
Significant portions of the northern and eastern shorelines are designated as protected nature reserves to preserve local flora.
The lake hosts an annual cross-swimming event that attracts participants from across the region.
Großer Alpsee is the largest natural lake in the Allgäu region of Bavaria, covering an area of approximately 2.4 square kilometers. It is located at an elevation of 724 meters above sea level within the Nagelfluhkette Nature Park. The lake serves as a significant hub for water sports, including sailing, windsurfing, and stand-up paddling. Its shoreline features a mix of reed beds, protected wetlands, and public swimming areas. A perimeter trail surrounds the lake, offering views of the surrounding Nagelfluhkette mountain range. During winter, the lake is occasionally frozen, though ice thickness varies significantly. The depth of the lake reaches up to 21 meters in its deepest sections. It acts as a primary recreational destination for the nearby town of Immenstadt. The water quality is consistently monitored and frequently rated as excellent for swimming.
The elevated viewing points along the southern trail near the village of Trieblings provide a panoramic view of the lake against the mountain backdrop.
Bring non-slip footwear for entering the water, as some entry points have gravel or stone beds.
The perimeter trail is well-maintained and suitable for cycling, but yield to pedestrians on narrow sections.
Parking areas can reach full capacity quickly on sunny weekends; aim for early arrivals.
Do not attempt to swim in areas marked for water sports, as high-speed sailing and surfing traffic pose safety risks.
The lakeside facilities and restaurants are primarily open from spring through late autumn, with some services limited during winter months.
Respect the marked nature conservation zones by staying on designated paths and avoiding swimming in protected reed areas.
