After a failed merger with Cova da Piedade in 2023, their Liga 3 license was revoked and B-SAD subsequently reformed and relocated from Lisbon to Almada to enroll and compete in the Setúbal district championships, the lowest tier of Portuguese football.

Os Belenenses created its SAD (Sociedade Anónima Desportiva; Public limited sports company) on 1 July 1999, to run its professional football section.

In 2017, the Court of Arbitration for Sport deemed the termination of the deal valid, ending the possibility of the Club being able to reacquire the 51% of SAD stocks, in order to regain control of its professional football section.

[7] With tensions mounting between Club and SAD, the protocol that regulated relations between both entities expired on 30 June 2018, ceasing any relationship between both parties.

Cova da Piedade approved a merger, with the new club assuming B-SAD's league position but taking on the name, identity and facilities of the latter.

B-SAD president Rui Pedro Soares said that the merger would be beneficial as his club's gymnasium and laundry had previously been several kilometers from their stadium.

[19] Silas was dismissed in September 2019, being replaced by under-23 manager Pedro Ribeiro,[20] who quit in January with the team one point above the relegation positions.

[22] On 19 October 2021, having needed a goal in the last minute of extra time to defeat minnows Berço SC in the cup, Petit resigned with eight months of his contract remaining.

[23] In November, under his replacement Filipe Cândido, the team fielded just 9 available players including two goalkeepers in a league match against Benfica, due to an outbreak of Omicron variant.

In the play-off, its final games before the merger with Cova da Piedade, the team lost 2–1 on aggregate to Länk FC Vilaverdense to begin its new life in Liga 3.

[27] However, after a failed merger with Cova da Piedade, their license was revoked and B-SAD subsequently reformed and relocated to Almada to play in the Setúbal district championships, the lowest tier of Portuguese football.