BOSTON – Former customers of FleetBoston Financial Corp. will temporarily lose the ability to pay bills and make transfers online while that system is integrated into Bank of America’s online network as part of a merger.

Charlotte, N.C.-based Bank of America said online bill paying and transfers will be unavailable for some of Fleet’s 5 million former customers during a 31/2-day period in June and for others during July.

In Massachusetts, Rhode Island, Maine, New Hampshire and Florida, online bill paying and transfers will be unavailable between 4:30 p.m. Thursday, June 16, and 6 a.m. Monday, June 20. In the second phase, customers in Connecticut, New Jersey, New York and Pennsylvania will not have those two services from 4:30 p.m. Thursday, July 21, until 6 a.m. Monday, July 25.

Customers still will be able to view account balances and transaction histories online during those periods, but will not be able to transfer money or pay bills online. Banking by phone will not be affected.