To Play in eu:
https://signup.leagueoflegends.com/en/signup/index in region select " Europe"

Open folder:
Riot Games\League of Legends\RADS\system

JaKoClubS> You have to change launcer.cfg locale.cfg and system.cfg
 [9:21 AM] <JaKoClubS> launcher.cfg*
 [9:21 AM] <JaKoClubS> launcher needs to be this for eu
 [9:21 AM] <JaKoClubS> gameProject=lol_game_client_sln
 [9:21 AM] <JaKoClubS> airProject=lol_air_client
 [9:21 AM] <JaKoClubS> airConfigProject=lol_air_client_config_eu
 [9:21 AM] <JaKoClubS> locale needs to be this
 [9:21 AM] <JaKoClubS> locale=en_gb
 [9:22 AM] <JaKoClubS> and system
 [9:22 AM] <JaKoClubS> DownloadURL=l3cdn.riotgames.com
 [9:22 AM] <JaKoClubS> DownloadPath=/releases/live
 [9:22 AM] <JaKoClubS> Region=EU