I find it can really depend. I have gone alone and not had one person make an effort to say hi to me or smile, and i have gone and made lifelong friends. It really just depends. Of course it does depend alot on you and your personality and attiude.
All the things mentioned above, swim up bar, pool games, excursions etc will certainly make it more likely and put you in a better situation where it’s easier to talk/meet people.
Probably the supper mealtime is the hardest if your a shy or self consious person.
But travelling solo can be alot of fun. If you don’t have family or friends who are able to travel when you want to, don’t let that hold you back!!