The 1909–10 Welsh Amateur Cup was the 20th season of the Welsh Amateur Cup. The cup was won by Johnstown Amateurs who defeated Bangor Reserves 2–1 in the final at Sealand Road, Chester.
First Preliminary Round Home teamResultAway teamRemarksCefn Albion0-3Acrefair UnitedJohnstown Amateurs3-2Esclusham White Stars
Second Preliminary Round Home teamResultAway teamRemarks Oswestry UnitedPonkey North EndPonkey scratchedJohnstown AmateursBala PressBala scratchedAcrefair United2-1Druids ReservesChirkRhos AthleticRhos scratchedBuckley Rangers0-3Shotton TownBuckley Engineers4-0Coed Talon Villa BoughtonMold TownFlint8-0RuthinBrynteg White Stars6-3GresfordSummerhill4-0Coedpoeth UnitedRossett1-1Brymbo VictoriaLlanfyllinCaersws UnitedCaersws scratched Shrewsbury Rovers5-2WelshpoolRoyal Welsh Warehouse (Newtown)4-1Montgomery
First round Home teamResultAway teamRemarksChirkJohnstown AmateursAcrefair United5-1 Oswestry UnitedConwy1-0Colwyn BayLlandudno Amateurs1-1Llanrwst TownMold TownBuckley EngineersFlintShotton TownLlanfyllin3-3Royal Welsh Warehouse (Newtown)Summerhill VictoriaSummerhillBrynteg White StarsBrymbo VictoriaLlanfaes Brigade (Brecon)RhayaderLlandrindod Wells2-0Builth WellsTowyn Rovers1-0PwllheliPortmadog2-0BarmouthLlanfyllin or CaerswsRoyal Welsh Warehouse (Newtown) Shrewsbury RoversNewtown ExcelsiorAberystwythAll exempt until the 3rd round.Carnarvon UnitedOak Alyn RoversRhos RangersBangor ReservesRuabon RangersHolyhead SwiftsLlanidloes United
Second round Home teamResultAway teamRemarksLlandudno Amateurs1-0ConwyFlintMold Town or Buckley Engineers Ellesmere Volunteers Malpas TownSummerhillBrymbo VictoriaRhayader0-1Llandrindod WellsPortmadog1-1Towyn RoversRoyal Welsh Warehouse (Newtown)2-5 Shrewsbury RoversAcrefair United1-1Johnstown AmateursAberystwythAll exempt until the 3rd round.Carnarvon UnitedOak Alyn RoversRhos RangersBangor ReservesRuabon RangersHolyhead SwiftsLlanidloes United
Third round Home teamResultAway teamRemarksBangor Reserves5-3Holyhead SwiftsLlandudno AmateursCarnarvon UnitedCarnarvon United scratched.Rhos Rangers4-1FlintSummerhillOak Alyn RoversRuabon Rangers1-4Johnstown AmateursLlanidloes United0-0Llandrindod WellsAberystwyth1-0Towyn Rovers Shrewsbury Rovers Ellesmere Volunteers
Fourth round Home teamResultAway teamRemarksAberystwyth7-0Llanidloes UnitedSummerhill2-1Rhos RangersLlandudno Amateurs0-0Bangor ReservesBangor Reserves3-1Llandudno AmateursReplay Ellesmere VolunteersJohnstown AmateursEllesmere scratched.
Semi-final ResultVenueBangor Reserves2-1AberystwythPorthmadogSummerhill2-4Johnstown AmateursEsclusham Ground, Rhostyllen
Final WinnerResultRunner-upVenueJohnstown Amateurs2-1Bangor Reserves Sealand Road, Chester
References