Question about Aran Island Tour
 

Hello,
My husband and I will be in Galway this May for 3 nights. On one of the days, we plan on taking the Aran Islands and Cliffs of Moher Day Tour with Aran Island Ferries. How far in advance should we reserve this tour? I know the reservation is for the ferry. While on Inis Mor we are interested in taking the Minibus tour. Is this something we need to reserve in advance, too? Or do we purchase our tickets for the minibus when we arrive on Inis Mor?
Thank you!