Going on vacation should be a time to relax, not be concerned about the scale. It is possible to go on vacation, enjoy yourself, and still stick to your goals.
From cruises to all-inclusive to weekend getaways, there are always healthy food choices. If you know you're going to your favorite restaurant for dinner, try to have a lighter breakfast or lunch.
Exercise on vacation does not have to be a chore, just keep it part of your regular routine. Resistance bands are great for vacations, they are lightweight, portable, and versatile.
If you don't have resistance bands, use your body (pushups, sit-ups, squats, lunges). Walk or move whenever you have the chance.
Enjoy your vacation, don't worry about the scale, just keep moving.