Following his loan spell with Bournemouth, Kepa is expected to join the Gunners on a reduced transfer fee.
According to reports, Kepa's contract includes a £5m buyout clause, which Arsenal is now prepared to exercise after agreeing to his contract terms.
It is worth noting that Kepa will join the team to compete with fellow Spanish goalkeeper David Raya, rather than replacing him.
During his time at Bournemouth, Kepa recorded eight clean sheets in his 31 Premier League appearances.
Originally, Kepa signed with Chelsea in 2018 for a then-record £72m transfer fee from Athletic Bilbao.