Citizens Bank has issued a $73 million construction loan for the next phase of the Roseland Property Co.’s Portside luxury apartment complex on the East Boston waterfront.

The Portside 5 and 6 buildings now under construction will include 296 apartments and 253 garaged parking spaces in a 5-story, 235,078-square-foot building on Marginal Street. Completion is projected in December 2017.

The facility will include a spin bike studio, golf simulator, demonstration kitchen with private dining, media room, indoor pool with locker rooms, rooftop desk with barbecue grills, fire pit and lounge seating.

Citizens also provided financing for Portside 7, the 181-unit initial phase of the development completed in 2014. Roseland leases the 26-acre property from Massport.