There are 181 9-letter words that start with 'sub'.
Note: These 181 9-letter words that start with 'sub' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with subs, subc, subt, subl, subm, subd, suba, subp, subj, subo, subv, sube, subi, subr, subg, subu, subb, subn, subf, subw, subh, subz, subk.
4-letter words start with 'sub' (2)