Yng Nghaergybi bydd angen cynnal archwiliadau ar nwyddau fel anifeiliaid, planhigion a chynhyrchion sy'n dod o anifeiliaid sy'n dod i Gymru o Weriniaeth Iwerddon.
At Holyhead inspections will be required on goods such as animals, plants and products of animal origin entering Wales from the Republic of Ireland.