The Helenesee is a lake near by Frankfurt (Oder) in the Oder-Spree-Lake area. It is a recreation area and lies in Landschaftsschutzgebiet Former mining area Finkenheerd, in which also the adjoining south-east Katjasee located. The Helenesee station on the railway line Königs Wusterhausen-Beeskow-Frankfurt (Oder) of the line RB 36 is hourly by trains of Niederbarnim Railway (NEB) approached.
The lake is around 220 hectares in size and at 56.63 m the second deepest lake Brandenburgs. It is located in the middle of the Brandenburg pine forests around eight kilometers south of Frankfurt (Oder) and is one of the cleanest lakes in the state. Its good water quality and the kilometers of textile and nudist beaches gave the lake its nickname "Small Baltic Sea".
Because of the nature of its bottom, the lake is at divers popular. It was created from the former lignite opencast mine "Grube Helene" (1906 to 1958). Several diving clubs, one diving school and a submarine for tourists are located at Helenesee.
A sporting and cultural program such as children's programs, beach parties, live bands and disco evenings is offered from Easter to October. There are among other things Tennis– and volleyball courts, soccer fields, the offers of the diving and surfing school as well as the boat, pedal car and Fahrradverleih available. These are the highlights of every season Helene Beach Festival for the young generation and the traditional Neptunfest for families.
A New Year's dive is organized annually by the Frankfurt underwater club Helene. Participants like the specialists of Federal Police, who have been taking part in the traditional event for several years, use helicopters to simulate rescue operations in flowing water.