Betis have been in touch with the 26-year-old’s representatives all summer but it has taken the final day of the window to agree on a deal.
The Spanish clubs were making space in their wage bill for Bellerin and the Spaniard is now on his way back to Spain.
Betis have agreed a deal with Arsenal to sign the right-back on loan for the rest of the season with no option to buy.
Bellerin will undergo a medical in London this afternoon before he can fly out to Spain to complete the formalities of the move.
The 26-year-old has spent his entire professional career at Arsenal since joining the club from Barcelona in 2010.
He has been keen to move on from Mikel Arteta’s side since last summer and is not part of the Arsenal manager’s plans.
The Gunners are set to sign Bologna defender Takehiro Tomiyasu as a replacement for the Spaniard.
