The gameplay of Mario Tennis Aces consists of playing matches of tennis with various characters from the Super Mario series. Players can pick from Mario, Luigi, Wario, Peach, Waluigi, Daisy, Rosalina, Yoshi, Donkey Kong, Bowser, Toad, Toadette, Chain Chomp, Bowser Jr. and Boo to play as.[1] Similar in fashion to previous installments of the series, Aces incorporates many techniques, such as "topspins", where the ball travels parallel to the direction hit, "slices", where the ball curves to one side when hit, and "lobs", where the ball travels upwards.[2]

Aces adds several new mechanics to the Mario Tennis series. Using the motion controls of the Joy-Con, the player is able to initiate a "zone shot", where the player can aim directly where the ball will go while the game enters a paused state[3]. If the opponent counters the zone shot, their racket will take damage.[4] When a racket is hit with a zone shot three times, it will break, forcing the player to forfeit the match if it is their last one. Players have multiple rackets to use each match.[5] However, players are able to counter a zone Shot without taking damage using a "block", which can be performed by hitting the ball with perfect timing. Another new addition in Aces is "zone speed". When a player activates zone speed, the match goes into slow-motion, but their character moves at normal speed, making it so faraway shots are easier to reach.[2] The zone shot and zone speed moves use up part of the players “energy gauge”, which is filled and depleted throughout the match. To refill the gauge, the player must keep a rally going with the opponent or use the "trick shot" ability.[6]

The trick shot ability enables the player to quickly travel to where the ball will land.[7] If the trick shot succeeds, then the player's energy gauge will increase dramatically. However, it is easy to misjudge the timing and therefore is a risky move to make. Another ability available to players at the cost of their energy gauge is the "special shot". To activate it, the player must have a full energy gauge. The ability unleashes an extremely powerful shot that has the power to break the opponent's racket regardless of its current damage. However, the special shot can be blocked similarly to the zone shot. Aces also has a "simple rules" mode, where only simple shots are allowed and zone shots, zone speed, trick shots, special shots and the energy gauge are nonexistent.[1]

The game also features an online multiplayer mode, where tournaments can be set up, as well as singular matches.[8] This mode is also able to unlock additional outfits and characters. Another gameplay mode is "swing mode", where players are able to swing the Joy-Con controllers to simulate hitting the ball with a tennis racket, similar in fashion to Wii Sports.[9] In addition to regular tennis matches, the game offers a story mode similar in fashion to Mario Tennis: Power Tour