ALPENA — Thunder Bay National Marine Sanctuary (TBNMS) is preparing to welcome Viking Expedition ships back to Alpena for its fifth year, according to a TBNMS press release on Wednesday.

Throughout the 2026 season, the 665-foot sister ships Polaris and Octantis will make 20 scheduled stops in Thunder Bay, bringing hundreds of guests ashore at the Great Lakes Maritime Heritage Center to explore downtown Alpena and Northeast Michigan.

Visitors will explore the region through lighthouse tours, nature hikes, downtown walking tours, aerial-sightseeing, fishing charters, and glass-bottom boat shipwreck adventures, according to TBNMS.