Both players join on free transfers after their previous contracts, with Athletic Bilbao and FC Dnipro Dnipopetrovsk respectively, expired.
|150/1||Fulham are 150/1 with Coral to finish in the top four next season
Venezuelan centre-back Amorebieta, who has made over 250 appearances for La Liga outfit Bilbao, is pleased to have joined the west London club and cannot wait to meet up with his new team-mates.
"I'm delighted to have signed a four-year deal with Fulham and I'm looking forward to competing in the Barclays Premier League next season," Amorebieta told the club's official website.
"I'm impressed with the talent already at the Club and I look forward to meeting the players for pre-season training in July."
Midfielder Boateng, who has also played for Panathinaikos and Getafe, has only joined on a one-year deal (with the option for a further year), but he is also delighted to have made the switch to Fulham.
"I'm very happy that I have signed and I want to thank the Chairman, the Manager and the Board at Fulham Football Club," he told the club's official website.
"I've been working hard to come here and I'll do my best for the club. It's been a long road for but now I'm here I'm so happy and I can't wait to start and give everything I have."