I have mentioned and duplicated this in a few posts, so finally, I decided to make a proper page for the topic.
What SCUBA diving gear should I own?
I recommend carrying with you a couple of retractable tethers. They are inexpensive, and you will want to hook your dive computer/pressure gauge on one and your flashlight on the other.
You will need two (2) duffle bags for your gear: a personal mask, snorkel, fins, booties or socks, gloves, and maybe even a personal regulator. Why 2 duffle bags? One bigger duffle bag is made of solid fabric for airport travel. And one smaller duffle bag for the beach made of mesh; you really want all the sand and moisture to escape before you go to the hotel room or airport.
Any seasoned diver will tell you that one thing you want to own is a regulator. First, sharing a mouthpiece with people you do not know is discussed. Secondly, you want to understand how to operate your dive computer.
Finally, I added my own free-diving fin and mask set. You might want to choose shorter fins for diving, especially in tight caves. I like my long fins.
The mask has a small field of view, but it holds well on my face and makes it easy to squeeze my nose for equalizing.
Some people choose not to carry snorkel tubes for SCUBA, but I do.
https://uki.blogspot.com/search/label/SCUBA