Inner-tubing is a popular water activity that involves floating on an inner tube down a river or other body of water. While "inner-tubing" is the most common term used to describe this activity, there are also several synonyms that can be used interchangeably. These include "tubing," "float-tubing," "river-tubing," and "lazy river tubing." Each of these terms describes the same activity and can be used depending on the context or location of the activity. Whether it's called inner-tubing or one of its synonyms, this fun water activity is enjoyed by many people of all ages and skill levels.