There are 5 Japanese MLB players played for the Oakland Athletics
Shintaro
Fujinami
RHP 
New York Mets
(Hanshin Tigers, Oakland Athletics, Baltimore Orioles, New York Mets)
藤浪晋太郎 (ふじなみ・しんたろう)
Bats: R Throws: R
Current Age 30
6-6, 180lb (198cm, 81kg)
MLB Debut:
2023-04-01 (28)
Akinori
Iwamura
2B/3B 
Tampa Bay Rays
(Tampa Bay Rays, Pittsburgh Pirates, Oakland Athletics, Tokyo Yakult Swallows, Tohoku Rakuten Golden Eagles)
岩村明憲 (いわむら・あきのり)
Bats: L Throws: R
Current Age 45
5-9, 200lb (175cm, 90kg)
MLB Debut:
2007-04-02 (28)
Hideki
Okajima
LHP 
Boston Red Sox
(Boston Red Sox , Oakland Athletics, Yomiuri Giants, Hokkaido Nippon Ham Fighters, Fukuoka SoftBank Hawks, Yokohama DeNA BayStars)
岡島秀樹 (おかじま・ひでき)
Bats: L Throws: L
Current Age 48
6-1, 195lb (185cm, 88kg)
MLB Debut:
2007-04-02 (31)
Keiichi
Yabu
(Oakland Athletics, San Francisco Giants, Hanshin Tigers, Tohoku Rakuten Golden Eagles)
藪恵壹 (やぶ・けいいち)
Bats: R Throws: R
Current Age 55
6-0, 200lb (183cm, 90kg)
MLB Debut:
2005-04-09 (36)
Hideki
Matsui
LF/DH 
New York Yankees
(New York Yankees, Los Angeles Angels, Oakland Athletics, Tampa Bay Rays, Yomiuri Giants)
松井秀喜 (まつい・ひでき)
Bats: L Throws: R
Current Age 49
6-2, 210lb (188cm, 95kg)
MLB Debut:
2003-03-31 (28)