Island Open

The Island Open as seen in the Game Boy Color version.

The Island Open as seen in the Game Boy Advance version.

The Island Open is the big tournament in Mario Tennis and Mario Tennis: Power Tour. The tournament itself is divided into singles and doubles tournaments between the Academy, the Union, the Empire, and the Factory.

Game Boy Color

Each match is 5 sets and 6 games long. Unseeded players must start in round one while seeded players are given a bye to round two.

Singles

In singles, the player will battle in order: Sammi, Spike, Emily, and lastly A. Coz.

Alex wins the singles championship in the Island Open.

Singles
	School	Seed No.	Character	Result
	Academy
		--	Alex/Nina	Winner
		2	Emily	Lost the semifinal to Alex/Nina.
		1	Kevin	Third place. Lost the semifinal to A. Coz.
		3	Mark	Lost round two to A. Coz.
	Union
		--	Sammi	Lost round one to Alex/Nina.
		--	Sean	Lost round one to Frank.
	Empire
		--	Elden	Lost round one to A. Coz.
		--	Ellis	Lost round one to B. Coz.
		4	Spike	Lost round two to Alex/Nina.
	Factory
		--	A. Coz	Runner-up. Lost the final to Alex/Nina.
		--	B. Coz	Lost round two to Emily.
		--	Frank	Lost round two to Kevin.

Doubles

In doubles, the player's team will battle in order: Sammi and Sean, Spike and Elden, and lastly A. Coz and B. Coz.

Alex and Harry win the doubles championship in the Island Open.

Doubles
	School	Seed No.	Team	Result
	Academy
		--	Alex/Nina and Harry/Kate	Winners
		1	Kevin and Emily	Lost the semifinal to A. Coz. and B. Coz.
	Union
		--	Sammi and Sean	Lost round one to Alex/Nina and Harry/Kate.
	Empire
		--	Ellis and Edgar	Lost round one to A. Coz. and B. Coz.
		2	Spike and Elden	Lost the semifinal to Alex/Nina and Harry/Kate.
	Factory
		--	A. Coz and B. Coz	Runners-up. Lost the final to Alex/Nina and Harry/Kate.

Game Boy Advance

Each match is 5 sets and 2 games long. In singles, unseeded players must start in round one while seeded players are given a bye to round two. In doubles, as there are a balanced number of teams, all teams start in round one. Dweezil is the defending champion of both the singles and (along with Mynx) the doubles championships.

Singles

In singles, the player will battle in order: Barb, Sass, Elroy, and lastly Willy.

Clay wins the singles championship in the Island Open.

Singles
	School	Seed No.	Character	Result
	Academy
		--	Clay/Ace	Winner
		2	Elroy	Third place. Lost the semifinal to Clay/Ace.
		--	Whisker	Lost round one to Chas.
	Union
		--	Chas	Lost round two to Mynx.
		--	Leon	Lost round one to Sheri.
		--	Mel	Lost round one to Willy.
	Empire
		--	Barb	Lost round one to Clay/Ace.
		1	Dweezil	Lost round two to Willy.
		3	Mynx	Lost the semifinal to Willy.
	Factory
		4	Sass	Lost round two to Clay/Ace.
		--	Sheri	Lost round two to Elroy.
		--	Willy	Runner-Up. Lost the final to Clay/Ace.

Doubles

In doubles, the player's team will battle in order: Chas and Mel, Dweezil and Mynx, and lastly Willy and Sheri.

Clay and Ace win the doubles championship in the Island Open.

Doubles
	School	Seed No.	Team	Result
	Academy
		--	Clay and Ace	Winners
		2	Elroy and Tori	Lost the semifinal to Willy and Sheri.
	Union
		--	Chas and Mel	Lost round one to Clay and Ace.
		--	Leon and Peter	Lost round one to Elroy and Tori.
	Empire
		1	Dweezil and Mynx	Third place. Lost the semifinal to Clay and Ace.
		--	Oscar and Barb	Lost round one to Willy and Sheri.
	Factory
		--	Sass and Chet	Lost round one to Dweezil and Mynx.
		--	Willy and Sheri	Runners-up. Lost the final to Clay and Ace.

Trivia

• In Mario Tennis: Power Tour, it is shown that Alex is canonically the winner of the singles and (along with Harry) the doubles championships of the Island Open.
• Between both games, the only Union player to make it past round one is Chas.
• The singles championship of Mario Tennis: Power Tour is the only time the player is not on the top-left of the bracket.
• As there are no mentions of any third-place matches, the third place trophies, when awarded, are shown to go to the semifinalists who had the highest rank going into the tournament.