May and June is typically the birthing and pupping time for Steller sea lions. During this time, the sea lions usually seek offshore rocks, islands and reefs like those at Cape Arago and are less likely to be inside the Sea Lion Caves. You might see nursing pups on the rocky shelf, below the southern viewpoint at Sea Lion Caves. California sea lions are also abundant on the Oregon Coast, but nearly all of these are males. For maximum sea lion activity, winter is the best time to visit Sea Lion Caves. As breeding season approached in spring, the sea lions leave the cave and remain in rookeries and outdoor haul out areas along the Coast until stormy weather in fall has them seek shelter within the cave.
Shore Acres State Park in Coos Bay and Yaquina Head in Newport are great areas for viewpoints that overlook Pacific harbor seal birthing and pupping areas in March and April. It is much more common to see nursing seals and seal pups than sea lions who prefer more isolated haul outs like those at Simpson Reef off Cape Arago.