These seasonal cruises, when ships relocate from one part of the world to sail in another, can offer as much as 70 percent off the price of regular voyages—though be prepared for more days at sea and potentially costly one-way flights. We asked cruise editor Jane Wooldridge to find the best ones.

Crystal Cruises, San Diego to Auckland, New Zealand; Cost per day*: from $212; 15 days
You’d ordinarily pay more than $400 per night on the luxury 922-passenger Crystal Symphony, where a recent update added Murano glass, Calcutta marble, and a 37-foot-long living wall. Guests have two days to explore Oahu, Hawaii, then a dozen more on board that are filled with filmmaking and art classes, magic shows, and lectures on maritime history and international relations. Oct. 28, 2014.

Celebrity Cruises, Rome to Fort Lauderdale, Florida; Cost per day: from $58; 16 days
This voyage aboard the newly renovated Celebrity Constellation calls at Cartagena, Spain; Agadir, Morocco; and the Canary Islands. That leaves plenty of time during the ocean-crossing for treatments at Canyon Ranch SpaClub, lounging at the pool, and vodka-and-caviar pairings at Crush lounge. Nov. 5, 2014.

Holland America Line, Sydney to Singapore; Cost per day: from $125; 16 days
During this sail aboard the 1,432-passenger Volendam, you’ll visit a bed of giant blue-lipped clams near the Great Barrier Reef’s Lizard Island, track the world’s largest lizard on Komodo island, and meet a traditional healer in Bali, Indonesia. Between excursions, the ship offers interactive cooking demonstrations and workshops with experts on local religions and customs. Nov. 22, 2014.

Windstar Cruises, Tahiti to Costa Rica; Cost per day: from $136; 22 days
The nonstop cruise from Papeete to Puerto Caldera recalls the epic Pacific voyages of Captain James Cook—but with considerably more comfort and style. Aboard the 148-person Wind Spirit, relax in the library or have a Thai herbal-poultice massage and take sunset yoga classes, all while flying under 69,000 square feet of sail. True, there are no excursions—but it costs about 70 percent less than Windstar’s regular Tahiti cruises. Nov. 14, 2014.

Oceania Cruises, Cape Town to Rio de Janeiro; Cost per day: from $286; 14 days
South African wine country, Namibia’s dramatic dunes, and the remote island of St. Helena are among the stops on this journey across the Atlantic. At sea on the Marina, it’s all about gastronomic pursuits, with hands-on classes at the culinary center and meals at nine restaurants, including Toscana, where you can sample 10 specialty olive oils. Nov. 28, 2015. 

*All rates are per person based on double occupancy.