Do you say I am going to snorkel or I am going snorkeling or snorkelling?

The correct phrasing would be "I am going snorkeling" or "I am going snorkelling," depending on the variant of English being used (American English vs. British English). The gerund form "snorkeling" or "snorkelling" is used to indicate the activity of engaging in the water sport of snorkeling. The phrase "I am going to snorkel" is less commonly used and may imply a future action rather than the immediate activity.