I have visited Vietnam before. It was a free trip with all the tours and meals paid for. Turned out to be a bit long as I was there for a year. We saw a lot of countryside, but most of the time we did not get a friendly welcome as went about our travels.
Carnival Liberty New Year's Eve 2007
Liberty of the Seas 5/2008+11/2009
Allure 1/16/ 2011
Vision OTS 2-14-2015
Freedom OTS 3/6/16