Successful boxers that started at a late age

[Let's go champ]

I know about Hopkins, Jason Sosa who else?

[Deevel916]

If I'm not mistaken, Sergio Martinez started pretty late as well.

[gmc_rfc_06]

Sergio was 23 or so.

[Sugar Adam Ali]

Nate Campbell was in his 20s..

Not sure but I think traver didn't turn pro til mid 20s, but I'm pretty sure he was involved in youth boxing..

[pacmanis1]

I wanna say Marciano started in his 20s.

[soul_survivor]

I wanna say Marciano started in his 20s.

Correct.
He was 20 when he joined the boxing team for the army and then boxed as an amateur for a short time.

Like most fighters who start late either pro or am, he did have a sporting background, mainly in baseball. Martinez had a very sporty background, involved in cycling (would lead to later knee damage), football and some other stuff. I think he came to boxing in his late teens.

[Chrismart]

Adonis Stevenson if i'm not mistaken. I think he was in prison in his early twenties.

Froch got into the sport a little later than most also i think.

[Tony Trick-Pony]

Obviously GGG, Kovalev, Lomachenko, half the Eastern Euro roster...

Marciano too.

[yngwie]

Antonio Tarver turned pro at 29, the funny thing is that he was fighting since he was a kid (he fought Roy Jones when he was around 11-12).
In cases of fighters without amateur experience, jess willard turned pro at 29 i believe.
deontay wilder had very little experience when he won the olympic bronze.

[John Locke]

Obviously GGG, Kovalev, Lomachenko, half the Eastern Euro roster...

Marciano too.

Those guys come from deep boxing backgrounds, they were all solid amateurs and not late starters.