Aaron Ramsdale will undergo a medical with Southampton today ahead of his move from Arsenal.
It is understood the fixed fee is £18m, potentially rising to £25m if performance-related add-ons are met.
Negotiations are continuing to agree the other aspects of the deal, but it is looking positive for all sides that it will be completed.
Ramsdale – under contract with Arsenal until 2026 – has been told he can leave the club if the right offer is made.
The England international lost his position as first-choice ‘keeper for the Gunners to David Raya last season, leading to speculation he would leave this summer.
Saints had looked to be signing Feyenoord’s Justin Bijlow earlier this week, but decided to pull out of the deal at the medical stage on Tuesday.
Meanwhile, Arsenal have many of the details of a deal in place to sign Espanyol goalkeeper Joan Garcia as a replacement if and when Ramsdale leaves, and are understood to be in a good position to close it.
When does the summer transfer window close?
The 2024 summer transfer window officially closes on August 30 at 11pm UK time in the Premier League and 11.30pm in Scotland.
The Premier League has brought forward Deadline Day to link up with the other major leagues in Europe. The closing dates were set following discussions with the leagues in England, Germany, Italy, Spain and France.