The Summer Carnival is a celebration held from the end of May to the middle of September every year. Starting in 2015, this event is also available during the middle of February for two weeks. During this event, a third currency is added, and can only be used during the Carnival, Tickets. There is a "Print and Play" shop, games to earn tickets, and an additional shop to buy tickets with Gems. It has been running since 2012, and each year, new prizes arrive.
The Summer Carnival is set in a grassy field surrounded by a dense forest. The center of the carnival has a large, circular step down with a grass area in the middle where there is a round platform. The platform has a box, chest, bag, and crate placed on it. Fancy light posts are positioned around the edge of the circular area. Extending out from the circular area are many dirt paths that lead to different points. Along the top edge of the forest, there are a variety of tents for games and shops. At the top left of the carnival, a large inflatable bounce house cuts into the forest. Far off on the left side of the carnival is a small campfire with wooden log seats.
The carnival includes the Summer Carnival Shop, which is divided into four parts, as well as several different mini-games that are all arranged in a zigzagging row of sorts. Starting from the right side of the carnival, there is the ticket shop, Phantom Ball, Dunk-A-Phantom, Carnival Darts, the den item shop, the clothing shop, Candy Catch, Whack-A-Phantom, and finally the plushie shop. To the left of the plushie shop is a staircase that leads up to a large, inflatable bounce area that causes animals and pets to jump high into the air; this bounce area consists of two levels with a slide that leads back down to the Whack-A-Phantom game. There is also a Print and Play activity located at the bottom-right of the carnival and a Cotton Candy Machine near the bottom-left.
- The bouncy castle and the firepit were added to the Summer Carnival in 2015.
- When a player enters the Summer Carnival for the first time, they will receive 500 tickets.
- When the Summer Carnival is over, Jammers will be able to keep their tickets for the next year.
- When the Summer Carnival first appeared early in 2015, it was not announced.
- When the Summer Carnival returned in May 2016, a glitch was introduced that caused the loading screen to display forever after the player finished playing a full-screen mini-game from the Games tab while inside the Summer Carnival.
- Two weeks before the carnival leaves Jamaa, all of the shop items (excluding the Tickets themselves) go on sale for 50% off.
- From February 9, 2018, to February 14, 2018, it is available as a temporary party rather than a permanent party, and its party banner says "Carnival" instead of "Summer Carnival." It was created to celebrate the Carnival period as well as the Portuguese carnival, which occur at that time.
- At the 2017 Summer Carnival, many of the items got rare tags and were replaced with new color variants.