Warehouse workers and truck drivers at Los Angeles ports are planning to launch a three-day strike Oct. 1, aiming to put pressure on logistics companies they claim owe them back wages.

The action targets XPO Logistics Inc. and NFI Industries and marks the 16th strike mounted by the Teamsters union in recent years among nonunion workers at the ports of Los Angeles and Long Beach, according to the labor group. Rather than focus on slowing work at the ports, the...