Britain is one of the easiest places to use Interrail in, the entire domestic network is turn-up-and-go, no reservations are required except for sleeper trains and Eurostar to France/Belgium/Netherlands.
If you want reservations they are available free of charge from any staffed station or online from GWR.com
Intercity trains aren’t typically as fast as many continental countries but IMO more than make up for with the frequency (all main routes are at least hourly, many are every 30 minutes or less) and ease of use, just board any train you like and go.
Regional trains are far better than the likes of France, again they are for the most part frequent and run early morning to late at night, you have to go somewhere very remote to find the rubbish 2-3 trains per day that SNCF chuck out on many regional routes.
1st class is particularly good on the main routes IC from London to Birmingham, Liverpool, Manchester, Leeds, York and Scotland as they offer complimentary hot/cold food and drinks, other IC routes generally offer tea/coffee and snacks.
Reliability and punctuality are not nearly as bad as some complainers will suggest, the majority of services run as scheduled and are on-time. Disruption happens like anywhere and post-COVID has been particularly bad with staff shortages causing timetable reductions and more cancellations than usual, There is also a major disruption upcoming with severe strikes happening next week and possible beyond.
Ireland is also an easy country to use Interrail in as reservations are also not compulsory for any train. Only certain Irish Rail Intercity routes allow reservations which can be obtained free from Irishrail.com but you can travel without them as many locals do.
The rail network in Ireland is more sparse, particularly in Northern Ireland. Most main cities/towns on the island (with some notable exceptions) have stations but the routes and frequencies offered are lower than many countries.
If spending a whole day or more in Northern Ireland it would not be worth using a day on an Interrail pass as a local day ticket for public transport with in Northern Ireland costs £16.50 which includes bus and coach services that fill the large gaps where no rail lines exist.
Yes, thats it-dense network in EN, less so in Scot-but very scenic, use Ferry (discounted, but still not very cheap between islands) and IN IE its like a star-only lines to/fro Dublin, not really cross country.
The major prob as for now are the strikes-for which UK is known to have many-but so do FR and ITaly.
Thank you so much @Al_G and @mcadv !
Easiest for me is going to London first. I already have some ideas for Scotland, but I’m open to suggestions for England
I would travel for max. 2 weeks so i’m not sure I have time to visit Ireland, but if so, what ferries can I use ? Are there discounts with the interrail pass ? Or maybe even day trips to visit some islands ? That would be amazing
PS: I just saw there is a discount (30%) on Stena Line on :
- Cairnryan - Belfast
- Liverpool - Belfast
- Holyhead - Dublin
- Fishguard - Rosslare