SeaWorld Entertainment Inc. said Tuesday it would lay off 320 employees as part of a restructuring and cost-cutting initiative as it continues to plan for a post-Orca future.

In March, SeaWorld said it would stop breeding killer whales, as known as Orcas, and cease its theatrical shows featuring them, as heavy public scrutiny in recent years pressured attendance. SeaWorld has said it wants to highlight its animal-rescue efforts and add more educational and advocacy work to its parks.

Tuesday,...