This lake really was my personal highlight of this trip. It’s a glacier lake connected to the ocean by a short river.
Beside walking around the lake, you can do a boat trip with an amphibian vehicle or rubber-boat. There is also a snack-bar, similar to the one in Landmannalaugar. Here, you can also find restrooms and buy the tickets for the boat-trips.
When standing at the lake, pay attention to the wind. When the wind comes down the glacier and crosses the lake, it is very cold! Even, it the wind is kind of slow. Although the clothing is usually warm enough, this wind is way colder! So, be prepared and dress up with an additional layer of clothing.