The visitors led 19-0 at the break and added 20 more unanswered points after the break.
Coach Rowland Phillips takes his side to face Ireland in Dublin on Sunday, 22 January.
They then go to Rome to face Italy in their Six Nations opener on Saturday, 4 February.
Kerin Lake, Lowri Harries, and debutant Jaz Joyce scored two tries apiece while Jess Kavanagh-Williams also touched down.
Robyn Wilkins converted two.
Wales Women: Dyddgu Hywel (Scarlets); Jessica Kavanagh-Williams (Scarlets), Kerin Lake (Ospreys), Rebecca De Filippo (Newport Gwent Dragons), Elen Evans (Scarlets); Robyn Wilkins (Ospreys), Keira Bevan (Ospreys); Cerys Hale (Newport Gwent Dragons), Lowri Harries (Scarlets), Amy Evans (Ospreys), Rebecca Rowe (Newport Gwent Dragons), Mel Clay (Ospreys), Sian Williams (Newport Gwent Dragons), Rachel Taylor (Scarlets), Sioned Harries (Scarlets).
Replacements: Gwenllian Pyrs (Scarlets), Kelsey Jones (Ospreys), Caryl Thomas (Scarlets), Siwan Lillicrap (Ospreys),  Shona Powell-Hughes (Ospreys), Sian Moore (Newport Gwent Dragons), Elinor Snowsill (Newport Gwent Dragons), Gemma Rowland (Newport Gwent Dragons), Adi Taviner (Ospreys), Jasmine Joyce (Scarlets).
Wales Women comfortably beat their Spanish counterparts in Alicante in their first warm-up ahead of the 2017 Six Nations.