KYC (Know Your Customer) checks are required by the Costa Rica Gambling authority as a anti-fraud measure once you reach €2300 in deposits.
or on withdrawal requests

A KYC check is a confirmation of the following information from the account holder:

Valid Picture ID: A passport, driver’s license, or national ID card. The identification must be a valid government-issued photo ID.
Utility Bill: A utility bill no less than 3 months old showing that you live at the address listed on your sunclubcasino.com account.
Confirmation of Payment Method: These statements should be no older than 3 months and must include the account number and account holder’s name:

Bank Transfer: Bank statements should include the account holder’s name and address and should match the details on their sunclubcasino.com account.

Credit Cards: Front and back images of the credit card are required and the backside of the card must be signed. The front image must clearly show the first 6 and last 4 digits (1234 56XX XXXX 1234).

E-Wallets: E-Wallets follow the same general rules as bank statements. They should include the account holder’s name and address and match their sunclubcasino.com details. For customers using e-wallets that do not provide paper or PDF statements, a screenshot of the account details showing the customer name and address is required.

The player will have 30 days to complete their KYC check once their total deposits exceed €2300. Documents should be uploaded to sunclubcasino.com at My Account.