Same reason why I sometimes see some girlfriends arrive at the nude beach...and just one goes completely nude right away while the other(s) keep something on.

Body-confidence.

Sometimes they've just "got it"; they are just comfortable with themselves and don't care about being seen topless. Other times it's because they've spent time before sunbathing topless; and they just prefer not bothering with a top. And other times they are just the "daring type" and want to rise up to the challenge of being publicly topless - because the opportunity is just there.

It's always funny to me seeing the friend's facial expression when their friend flings their bikini off. It's an expression of temptation. You can tell they envy their girlfriend. But are held back by whatever hang-up they have. Some of them eventually go "oh screw it!" and join their friend. I've seen that happen many times too.

topless girls are happier ...
 

the girl on the right is embarrased to have her top on!

very interesting and I can only say I totally agree with you...
it's more with the ''young'' people that we can see this thing IMO...

nice thread

Why not topless?
 

It's commom enough to see friends on the beach with a different dress code
One is topless while the other is not ...
Why do women go topless (or not) on the beach?
WWhat are the different thoughts and sensations of them?...
What's your answer to these questions?

embarrasment or excitement?
 

Many women stay covered only because they think their body is not beautiful enough to strip. It's not shame it's fear of not being fit enough.
Sometimes it's their men who push them to undress by showing their boobs on the beach because it excites them to show them ... in other cases it's the women to excite or embarrass their husbands or boyfriends ...
When women in bathing suits and other topless women are together, often the most embarrassed are the ones who dress the most!

embarrasment, condidence or excitement?
 

These photos suggest some possible answers.

In the pics 1, 2, the topless girl, despite is not used to go topless (pale tits), seems not care being in a crowed beach with many other women with theri tops on. Her firend on the contrary is shy and keeps her tops on with her hands ...

In pics 3, the topless girl seem a little bit worried, while her boyfriend is not happy of her (not usually) exposed tits.
The oher girlwith her top on, likely is asking her what's feeling ...

Anyway, intriguing situations!

The only one
 

The braver one

nice selection.
Also in these photos, in some cases topless girls seem happier, in others those who keep their tops on ...
what's the thoughts behind that?
Here the fully dressed girls is clearly unhappy/embarrassed !

Topless girls and swimsuited ones with boyfriends, hubbies and/or friends ...
Why do women go topless on the beach, while others instead wears the top, hiding their tits?
Are their men asking them to show tits?
Are their men asking them NOT to show tits?
When other girls are swimsuited the man of the topless woman is embarrassed or excited?
What are the different thoughts and sensations of them?
...

2 clothed - 3 topless - 1 naked
 

I've seen an even more extreme example. A group of friends (maybe early 20s)at a clothing optional beach, 2 stayed in bikinis, 3 went topless and 1 went totally nude. It really took me by surprise as often friends have similar attitudes or copy each other.

All of them had good bodies and were tanned. Lots of others naked nearby. The naked girl had a landing strip and most others on the beach were bald, so unless they were really hairy there was nothing to worry about.

All I could think was the naked one must be mega confident and the 2 that left their bikinis on must be really shy.

If I'd been braver I would have asked what was going on!