Pokemon: Magikarp Jump is a mobile game in which the player is a Pokemon trainer, training their Magikarp to jump as high as possible. The player starts the game by catching and naming a Magikarp. Progress through the game is achieved by training Magikarp, feeding it, competing in Leagues, and by random events.
In-game purchases are made with two kinds of in-game currency.
Coins are awarded frequently to the player for completing small in-game tasks such as completing League challenges, acquiring in-game achievements, and via random events. Coins can be spent to upgrade the player's training items and food items.
Diamonds are acquired via in-app purchases and significant events such as defeating all challengers in a League. They can be spent on other Pokemon, such as Pikachu, which accelerate Magikarp's training through unique abilities.
Magikarp can be trained once per in-game day. The player uses training items such as the "Sandbag Slam" to train Magikarp and acquire "Jump Points" (JP). Magikarp's JP stat determines how high it can jump. Various training items give a fixed amount of JP with occasional random variation. Training items can be upgraded using in-game coins.
Leagues are where the player's Magikarp competes with computer players' Magikarp in a competition to jump the highest. In each League the player must face five challengers, each with progressing difficulty. Each challenge consists of a single duel with the opposing Magikarp. The final challenger yields a unique item to the player, such as a Light Ball which will add a Pikachu to the player's home.
Losing a League challenge will prevent the player from competing in a League for 1 hour and 30 minutes, but this time constraint may be avoided by using an "LP Restore" item.
After the player has leveled up Magikarp to its maximum attainable level and completes a League, the Magikarp is "retired" and the player must catch a new one. The new Magikarp will have improved stats over the previous and will consequently train faster. The player will then train and once again compete with their Magikarp in a more difficult League.