Normal
Some do, some don't, aout half & half..or maybe a little more than half. Usually a couple of bucks for a tour guide and/or bus driver. Some tour guides are REALLY good, and when you get done with their tour you really feel like giving them something extra. Others just hold out the tip jar as a matter of course. We go on snorkling trips a lot, and sometimes those folks really work hard...much more than driving a bus or talking for a couple of hours...they can make or break a tour like that. My rule is if I really enjoyed it I tip them, if I didn't or it was just OK, I don't. If you feel you don't want to tip, you'll have plenty of company, so don't let it bother you. I'm sure you'll get the usual opinions about their company making all the money and them getting nothing...don't let that bother you either, the guides do quite well on most of these islands and ports.