Tomiyasu has been a free agent since the summer, following a mutual agreement with Arsenal to terminate his contract a year early.
Injuries plagued his career in North London, and manager Mikel Arteta decided not to renew his contract as fears over his constant fitness doubts grew.
Flashscore report that the 27 year old has put pen to paper on a “prove-it” contract, which won't cost Ajax any money until Tomiyasu plays for the side.
Director of Football Marijn Beuker commented on the deal, which he says was thought over many times due to his persistent injuries.
"Takehiro has proven himself to be an excellent defender with extensive experience in several top leagues. He is an intelligent, two-footed defender. Together with the scouting department and the coaching staff, we have reviewed a lot of footage of him in recent weeks, and everyone is enthusiastic. His injury history was also an important consideration.
“From the outset, he has worked hard on his recovery, the medical staff have assessed him thoroughly, and once his work permit is finalised, he can immediately join group training."
"Although he still needs to regain match sharpness, we believe that, given his experience, he will pick this up almost straight away. Contractually, we have also found a good way to enter into a collaboration together. All in all, we expect that with Takehiro we have brought in a player who can bring more balance to our relatively young, but very talented squad in the short term."
The Japanese international has played just one game since May 2024 and his contract status reflects the club caution to tying him down to a long term deal before he can prove himself.