ΔE 8.1, close: similar, with a visible difference side by side. Steel Blue is a little darker, more muted, cooler than Sea Blue.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Steel Blue is a little darker, more muted, cooler than Sea Blue.
The same difference applies the other way round: Sea Blue is a little lighter, more saturated, 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 Sea Blue on the colour wheel See Steel Blue on the colour wheel
All matches: Sea Blue equivalents · Steel Blue equivalents