Business Directory Go back to directory. Natural Oasis Swimming Pool Natural Oasis Swimming Pool Work Phone: (406) 234-7445 (Summer Only)work Biography Owned & Operated by the City of Miles City, The Natural Oasis is our local swimming pool. It includes lifeguards, beach, docks, and summer swimming lessons. Open Daily 1:00pm – 7:00pm June through August Fees 6 / under Free 7-12 yrs $1.00 13-17 yrs $1.50 18 and up $2.00 Season Passes Individual: $35 each 2/$50 Family Pass: $100/ for up to 5 people