|This area is part of Evergreen Island, the Christmas event island. As such, its accessibility is limited to its opening times, which are between December and January.
Evergreen Island Crystal Cave is a Evergreen Island area connecting Evergreen Island Valley Path, Evergreen Island Waterway and Evergreen Island Village south area. It is notably one of the easiest places to capture a Axew and Sableye.
This is one of the three ways of getting Christmas tokens, while the other two are via Christmas Chris boss and Trevor's Hide & Seek game. This task requires the player to battle and defeat 10 trainers in sequence. The trainers teams will be randomised, using the Pokémon listed below. Succeeding in defeating any amount of trainers, the player will be awarded one Christmas token for each win they get, additionally if they beat all 10 trainers the player gets rewarded five extra Christmas Tokens at the end. This can be used at the shops in Evergreen Island Village to buy several goods. Disclaimer the Battle Underground can be challenged 3 times a day.