If you have forgotten your Pokémon Trainer Club username, follow the account recovery steps below.
Pokémon Trainer Club Account Recovery Steps:
1. Go to https://sso.pokemon.com/sso/login
2. Click on "Log in"
3. Click on Trouble Logging in?
4. Click on "I forgot my username"
If you have forgotten your login password, please reach out to the Pokémon Trainer Club (https://club.pokemon.com/us/pokemon-trainer-club/forgot-password) for further assistance.