ΔE 14.3, fair: the same colour family, but not a straight swap. Sky Blue is a little lighter, cooler than Surf Aqua.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Sky Blue is a little lighter, cooler than Surf Aqua.
The same difference applies the other way round: Surf Aqua 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 Surf Aqua on the colour wheel See Sky Blue on the colour wheel
All matches: Surf Aqua equivalents · Sky Blue equivalents