Sonic Team boss Takashi Iizuka wants to make Sonic Adventure 3 eventually, but right now there are no plans to make this sequel. He also points out that there will be no Chao Garden title as he considers this to be part of the Sonic Adventure experience.
"When we talk about Chao Garden specifically, I know everyone's like 'I want Chao Garden, I want Chao Garden. But Chao Garden is a piece... it's part of the whole Sonic Adventure series of games", he said in an interview with VGC.
Although there are no plans for a new Adventure, there might still be a little hope for the future.
"I think at some time I'd like to say 'hey, yeah, we're making Adventure 3', but we don't have plans for that yet. It's just one of those things that if, if the stars align and it can all happen, then yeah, we'd love to make it."