Which Ocean

• Unless you're traveling a leg of a world cruise crossing the Pacific Ocean to or from Asia, most transatlantic cruises cross the Atlantic Ocean.
  
  

When

• Cunard offers transatlantic cruises year-round on ships built like ocean liners. Other cruise lines mainly schedule ocean crossing in the spring or fall to reposition their ships on different continents. Repositioning cruises may be bargain-priced.
  
  

Weather

• A northerly route on any ocean can be rough, cold and foggy any time of the year. Cruise ships will sail as far south as possible if bad weather is forecast.
  
  

Dress Code

• Transatlantic cruises tend to be dressier, with formal evenings every two or three nights unless you're sailing on line that's committed to casual dress anytime.
  
  

Activities

• Guest lecturers or special entertainers often supplement the usual shipboard pastimes of bingo and art auctions.