Traffic at the ports of Los Angeles and Long Beach rose in May compared with the same month last year, according to figures released Monday.

About 689,000 containers went through the Port of Los Angeles in May, up 8.2 percent from May of last year. Imports rose 8 percent year-to-year, while exports rose 2 percent. Empty containers sent overseas to be filled for imports were up 15 percent. Container volume for the first five months of the year is up 8.2 percent from the same period last year.

Meanwhile, about 600,000 containers moved through the Port of Long Beach in May, up 2.7 percent from May of last year. Imports rose 2 percent year-to-year, while exports were flat. Empty containers were up 7 percent. Container volume for the first five months of the year was up only 1.3 percent.

It was the busiest May at the Port of Long Beach since 2007, according to the port.

Port officials have attributed this year’s increasing traffic to an improving economy and retailers that are importing holiday season goods early to cover their bases should port labor negotiations fail and affect shipping.