Hi I am looking to have the date " January 31, 2015" translated. either written out in words or using the numbers. Thanks for any help

31 Eanáir 2015

In words, as in English, there can be several ways to say it, although they don't necessarily translate into exactly the same forms as are customarily used in English:

an t-aonú lá is tríocha d’Eanáir, dhá mhíle [is] cúig déag
the 31st [day] of January, two thousand fifteen

an t-aonú lá is tríocha de mhí Eanáir, dhá mhíle [is] cúig déag
the 31st [day] of the month of January, two thousand fifteen

_________________
I'm not a native (or entirely fluent) speaker, so be sure to wait for confirmations/corrections, especially for tattoos.