Which Pokémon games first enabled global trading and battling through Nintendo Wi-Fi?

Pokémon Diamond and Pearl first enabled global trading and battling through Nintendo Wi-Fi.

Released for Nintendo DS in Japan in 2006, Diamond and Pearl used the system’s wireless capabilities to connect players beyond the local Game Boy Link Cable or nearby wireless play. This made worldwide interaction a defining feature of Generation IV.

The games introduced the Sinnoh region and added 107 new Pokémon. Their online functions allowed players to trade and battle across greater distances, making it easier to complete collections and compare teams with international players.

Earlier games supported local trading and battling, while later games expanded online services and eventually moved to Nintendo Switch. The important milestone here is the worldwide connectivity introduced by Diamond and Pearl.