A:Answer The series 3 comes with two sizes of bands. If your wrist is on the large side, just get the 42mm. It’s a good half inch longer in the long band than the 38mm.
My wrists are large, and I bought the 38mm series 3 for my wife. The long band barely (and tightly) fit my wrist, but the 42mm long band fits comfortably in the second from last position.
Also there are innumerable custom Series 3 bands on Best Buy or Amazon that will fit literally any wrist size from third party vendors.