The former Anderlecht man has failed to make the grade in North London despite some early promising displays, and he may now have played his final game in an Arsenal shirt.
Lokonga's switch to Sevilla represents his third loan spell away from the Gunners following stints at Crystal Palace and Luton Town, and the Spanish giants also have the option to make his stay permanent.
Arsenal will reportedly receive €12m (£10.1m) should Sevilla decide to activate that clause, seeing them suffer a slight loss on the €17.5m (£14.7m) they forked out to sign Lokonga from Anderlecht in 2021.
The Belgium international was a protege of Vincent Kompany at Anderlecht and initially impressed in the Gunners engine room upon his arrival, seeing him earn his first senior call-up for his national team.
Lokonga made 24 appearances in his debut campaign at Arsenal, including 12 Premier League starts, but the form of Granit Xhaka and Thomas Partey in 2022-23 saw his game time severely restricted.
Lokonga granted transfer wish after Luton Town exploits
The 24-year-old was still a regular in the Europa League but did not justify his selections most of the time, seeing him loaned out to Crystal Palace for the second half of the 2022-23 campaign, where he was initially a favourite of Patrick Vieira.
However, he fell out of favour under the returning Roy Hodgson and was subsequently sent to Premier League new boys Luton Town for 2023-24, where both he and Ross Barkley received plaudits for their displays in the middle.
Lokonga came up with one goal and three assists in 19 matches for the Hatters, but he could not help save the Hatters from relegation, and he confirmed earlier this year that he and his agents were working on an exit from the Emirates.
The Gunners only have Lokonga under contract for another two seasons, and he could leave without registering a single goal or assist in 39 matches across all tournaments should Sevilla decide to keep him.
The Spanish powerhouses will reportedly cover his salary in full while he plies his trade in La Liga, and Arsenal will also receive 25% of any future sale if Lokonga stays with Sevilla.
Lokonga follows Mohamed Elneny, Cedric Soares and Arthur Okonkwo out of the Arsenal exit door this summer, although the former three all departed on free transfers following the expiry of their contracts.
The midfielder's exit is expected to be followed by confirmation of Nuno Tavares's sale to Lazio, while Emile Smith Rowe, Reiss Nelson, Eddie Nketiah, Aaron Ramsdale, Thomas Partey, Kieran Tierney and Jakub Kiwior could also leave in the coming weeks.