The South Bay ports posted cargo gains again last month as retailers continued to import goods for what may be a stronger holiday season than expected.

At the Long Beach port, 613,621 container units passed through in October, representing a nearly 36 percent increase from the same month last year. Even more significant: it was the best month for port traffic since October, 2007.

“Retailers have been very optimistic about shopping this holiday season and these numbers suggest that they think it will remain strong even after Christmas,” port spokesman Art Wong said. “We’re operating at a very high level here.”

Loaded imports rose 34 percent, from 227,064 container units to 303,168, while exports increased an impressive 27 percent to 150,581. The remainder was accounted for by empty container movement.

The Port of Los Angeles, which recovered faster a year ago from the depths of the recession, posted more modest gains, handing 682,385 container units in October, a 5.4 percent increase. Imports increased from 338,734 units to 349,545.

“We had a very strong October, 2009, and so didn’t have as far to come,” port spokesman Phillip Sanfield said. “What this confirms is that the holiday season came early this year at the port. We saw some of our strongest numbers ever in June, July and August while our October volumes are basically in line with what we would expect coming off a strong peak season.”