Gala Coral sold the bingo clubs to buyout firm Caledonia Investments, concluding a deal that was first announced in October.
Gala Coral will retain both the Gala brand and the websites Galabingo.com and Galacasino.com, although the clubs will continue to trade under the Gala brand through a licence agreement entered into by both firms.
The bingo clubs have more than 1.1 million active members and notch up around 15 million admissions a year. The business pulled in revenues of about £300m in the 12 months to September.
The move comes as Gala readies itself for its £2.3bn merger with Ladbrokes proposed in June, which is still subject to approval from the Competition & Markets Authority.
The planned Ladbrokes Coral merger will create Britain's biggest bookmaker, overtaking rival William Hill with almost 4,000 betting shops. The sale of some of Coral's units is seen as an attempt to ease competition regulator's concerns over the size of the new gambling giant.
Gala Coral's senior leadership team includes former HBOS chief executive Andy Hornby, who is the betting firm's chief operating officer.
Carl Leaver, chief executive of Gala Coral, said: "The disposal is another transformative step for Gala Coral, following the turnaround of the business over the past few years.
"Gala Coral remains focussed on growing and developing our retail bookmaking and online businesses, and concluding the proposed merger with Ladbrokes."
The move comes at a time of consolidation in the industry, which saw Irish betting chain Paddy Power and online rival Betfair agree to merge in August, creating one of the world's largest online gambling operations valued at £5bn.
In September, FoxyBingo owner bwin.party spurned online suitor 888 Holdings in favour of a £1.1bn cash-and-shares offer from Sportingbet owner GVC after a protracted takeover tussle.
A combination of new taxes on online gambling around the world and the need to invest in marketing and technology has led to consolidation across the industry this year.