To take benefit of the best prices you will need to prove you are a leisure traveller, en route to belfast-international airport, so you will need to provide either your flight numbers or yr holiday booking reference. I don't think you will need to provide this when you arrive at wakefield-westgate station but you may be asked to provide them on your journey from the station to the airport.
Going to belfast-international airport by train is great, you can sleep, read (even at night), play travel scrabble, or just stare out of the window... The other caveat to buying these inexpensive train tickets from the station to belfast-international airport is that there must be at least two adults travelling together. But another great advantage is that kids go free. All kids under five go free, and then one kidover five but under sixteen per adult travelling by train to the airport.
make sure you leave plenty of time to get to the airport early enough to eat, shop and so on, so check the times of trains from the station before you go. If you have spare time at belfast-international airport you can always read a book or play travel scrabble again! As you have bought yr train ticket in advance, you don't need to fret about the opening hours of the station.
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