The Southeast Asia & Oceania Shadowverse Open May Cup is one of the Monthly Cup tournaments. Day 1 of this online tournament is conducted in a Swiss draw format. 

The top 8 players move onto Day 2, contending for a cash prize in single-elimination matches. 

The player who has accumulated the highest league point score from January to September advances to the World Grand Prix. The Monthly Cup champions from April to September as well as two top league points earners will compete in the SEAO Contenders Cup.