The 23-year olds contract at the Mariners expires at the end of the season and he will join the Reds for the 2010/11 season and for a further season after that.
Boogaard has been in impressive form this term but said he was delighted to have sorted out his future with a new club although he did admit it was a weird situation.
"I've always respected the way Adelaide United both play football on the field and have done things off the field. The chance to move to Adelaide and join the club is something I'm really looking forward to," Boogaard said from Gosford.
"Obviously it's a funny situation. On a personal level, I'd still like to win with the Central Coast Mariners, but I'd also like to see Adelaide finish the season strongly as well, so there is obviously mixed feelings there. But on a professional level I'm still with the Central Coast, and hopefully we can beat Adelaide when we meet."