ΔE 19.1, loose: different enough that you should pick on purpose. Coral Blue is more saturated, warmer than Phantasmal Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Coral Blue is more saturated, warmer than Phantasmal Blue.
The same difference applies the other way round: Phantasmal Blue is more muted, cooler.
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 Phantasmal Blue on the colour wheel See Coral Blue on the colour wheel
All matches: Phantasmal Blue equivalents · Coral Blue equivalents