The player's partner Pikachu or Eevee can learn Secret Techniques, which are an overworld mechanic used in place of field moves. Three Secret Techniques have been revealed: Chop Down, Sea Skim, and Sky Dash.
Chop Down allows the player to clear away certain trees (like the field move Cut)
Sea Skim allows the player to travel across water (like the field move Surf)
Sky Dash allows the player to travel to towns and cities they have visited before (like the field move Fly)
Players can interact with their partner Pokémon outside of battle by selecting the Pikachu or Eevee icon on the main menu. It will sit on the player's arm, allowing them to pet, feed, and tickle it. By petting and playing with their partner Pokémon, players improve their relationship with Pikachu or Eevee and can receive in-game benefits such as presents. When the game is in handheld mode, players can use the touch screen to play directly with their partner Pokémon.
Once the player's relationship with their partner Pokémon reaches a certain level, their partner will sometimes give them a sign in battle (even when not the active Pokémon). If the player waves their detached Joy-Con when the partner sign appears, their partner will use its partner power. If it is the active Pokémon, it will use an exclusive move (Pika Papow or Veevee Volley); otherwise, it will boost the active Pokémon's stats.
Pikachu's exclusive moves include Splishy Splash and the partner power Pika Papow.
Splishy Splash is a Water-type move that has a chance to paralyze opponents.
Pika Papow's power increases depending on how strong the player's bond is with their partner Pikachu.
Eevee's exclusive moves include Bouncy Bubble, Buzzy Buzz, Sizzly Slide, and the partner power Veevee Volley.
Bouncy Bubble is a Water-type move that heals Eevee for half the damage dealt to the opponent.
Buzzy Buzz is an Electric-type move that paralyzes the opponent.
Sizzly Slide is a Fire-type move that burns the opponent.
Veevee Volley's power increases depending on how strong the player's bond is with their partner Eevee.