The styling of this bra is gorgeous. Unfortunately it doesn't work too well for full bust/small band, but such is life with non-custom bralettes. I think the XS would work best for someone who wears 28D/30C or smaller. Maybe you could get away with 28DD/30D. It's noticeably too small for me (I wear 26F, a sister size to 28E) in the boob-portion, despite the band being slightly loose.
Still, this is a beautiful offering from an ethical small business, I highly recommend it for the matrix-sized among us!
Is the list of sizes under which this listing will match for searches.
Why so many options?
This list of sizes is constructed using all the regions which
this brand labels their bras. Note that brands change this in
time so we include historic cup conversions.