We want to fly to London with a layover in Dublin. We'd like to just miss the leg of the trip to London and stay in Dublin a few days. We'll buy one way tickets from Dublin to London in advance for a few days after our scheduled arrival in Dublin, which is the least expensive option. My question concerns customs and such- will they let us enter Dublin even though we are supposed to carry on to London? In other words, are we allowed to just miss our flight and can we expect a hassle over it with the powers that be in the airport? Thanks all!!
In addition to being a violation of the fare rules, this is a bad idea. If you have a round-trip ticket, the airline will cancel the rest of the ticket if you skip a leg. At passport control in Dublin, it won't work either. Make your life easy and just fly to Dublin via Are Lingus or Icelandair or the like instead of pretending to be going to London.
A multi-destination search function can set you up with a three-leg ticket. Do it your way and you run the chance that your return ticket will be cancelled as well as alarming the airline security.
No! - Do not do this. The return ticket from London to the US will be canceled. Do the multicity search (Advance search option) from USA to Dublin then London to USA. Buy a one way from Dublin to London on AER Lingus, Ryanair, Easyjet or British Airways. Keep in mind the budget airlines such as Ryan Air or Easy jet will use other London airports such as Stansted (STN) or Southend (SEN). They are about an hour or more outside of London. Only pick Stansted if you want to see Cambridge before going into London. Additionally, if you got off in Dublin when you are supposed to go into London, your checked Luggage would end up in London and this gives it a high probability of ending up with lost luggage.
The only time I have not completed my journey was on my way from Zurich to London to Chicago. It was on my return journey and I had a family emergency in London. Luckily I had hand luggage only. I was in London visiting a family member in Hospital, I stayed two extra weeks and the only reasonable way for me to afford to get back to Chicago was to use airline points. AA wanted $3,000 for a flight change back from London to Chicago.
So, let's summarize.
1) Skipping one leg of a reservation cancels all remaining legs. In your case, your London back home flight will disappear.
2) When you try to go through Irish Immigration, it will show that you were on a flight to Dublin and scheduled to continue on to London. They will want to know why you are getting off. This will raise red flags. And Irish Immigration can be thorough.
As others have said, book yourself a open jaw ticket using the multi-city option.
Thanks everyone! So glad I asked.