ΔE 15.1, loose: different enough that you should pick on purpose. Aquamarine is a little lighter, cooler than Caribbean Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Aquamarine is a little lighter, cooler than Caribbean Blue.
The same difference applies the other way round: Caribbean Blue is a little darker, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Caribbean Blue on the colour wheel See Aquamarine on the colour wheel
All matches: Caribbean Blue equivalents · Aquamarine equivalents