Banyan Tree Oasis, is known for being a luxurious spa/club where amazing pool parties are thrown accompanied by an amazing night view Seoul has to offer. I had the chance to go ice skating with my good friend, even though it was one of the coldest days in Seoul. Despite the cold, we enjoyed the freshly groomed rink with few couples enjoying the romantic ambiance. The entrance fee is around 48,000W including the skate rental fee.
Besides the rink, you can rest/eat/chill/tighten your skates (like me in the picture) in the heated cabins.
Definitely a must try experience, but I would recommend going on a cold but not freezing weather so you can make the best out of it! : )