Hi Roselyn,
The
hop on hop off bus is a super way to see the city of
Dublin and visit all of the iconic attractions it has to offer.
Blarney Castle is a great place to visit, there are
day tours available from Dublin using such companies as
Paddywagon Tours,
Railtours Ireland, and
Extreme Ireland. Please have a look and see if they are able to offer you something that fits in with your plans before your cruise!
We hope this helps, please let us know what you manage to see during your short time with us.
Speak soon,