Abstract: A safety seat for land, air and sea vehicles is provided. The safety seat has a safety belt harness and can be secured between the floor and ceiling of a vehicle via securement straps provided above and below the seat. The safety belt harness comprises two lap belts and two shoulder belts that extend from the lap belts. Also provided is an activating device that, as an extension of the shoulder belts, is guided below a seat portion to the entry region thereof. A respective tensioning strap is yieldingly disposed between the shoulder belts and the front securement straps.