We can understand it is frustrating when a website doesn't play ball the way it should do!
Your trip from Skibbereen does indeed involve a change at Cork, so whether you decide on the bus all the way or change to the train really depends on the timings and costs involved. Once in Cork, Air Coach
service 704X to Dublin is an alternative and can be booked online for a guaranteed seat. Irish Rail
also has a booking online service for the Cork to Dublin route, well worth a look too.
We have an article page on Public Transport
that you may wish to have a look at. There are details of some of the main suppliers and also a link to Transport for Ireland
who has a super journey planner that can be very helpful with alternative provider information.
We hope this helps with your journey, there are several scheduled service times from Skibbereen to Cork and as my colleague Gordee mentioned, it would be very rare to find a completely full bus even in the busiest of times.
Please let us know what you decide on and that you complete your journey without any issues.