There are no Bet Olimp sister sites since its an independent online casino. Sites similar to Bet Olimp include Almighty Vikings, Fun88eu, BetBird, QuinnBet, Play The Pools, and JenningsBet.
Bet Olimp (betolimp.com) is part of OCG International, a gambling firm that is not licensed by the UK's Gambling Commission The company operates no other sister sites.