Airline/itinerary strategy for Iceland-London-Paris-Amsterdam

Go back thru Iceland on Icelandair.

Instead of looking for one-way tickets, look at multi city tickets (also known as multiple destinations or open jaw). Some airlines do not charge more for two one-way tickets, but many still do; by buying your trip SFO/OAK to KEF and AMS to SFO/OAK all on one ticket, you will probably save a lot of money.

So, go to Kayak Flights: https://www.kayak.com/flights and choose Multi-City. For your first leg, put in SFO to KEF, and under SFO be sure to check "include nearby airports." For your second leg, put in KEF to LON (all London airports). For your third leg put in AMS to SFO (again checking "include nearby airports"). See what comes up.

Then, redo all this, taking out the middle KEF to LON leg. Get the prices for just the transatlantic portion of your trip. Then go to Skyscanner http://www.skyscanner.com/ and price the KEF to LON separately. Sometimes it's cheaper to include it in the transatlantic ticket, and sometimes it isn't; only by checking for your dates can you know for sure.

Yes, it's a bit of work, but the only way to know all the options and their prices.

If you wish to fly Norwegian on the return (because they offer good pricing on one-way flights), you could return to London for the flight home. They fly London Gatwick to Oakland 5 days a week and the price right now is between $294 and $790 depending on the day. August is cheaper than July.

You can also mess around on the Icelandair website with round trip, stopover, multi-city and return from a different city options. And you can try one-ways for all segments of the trip to see how those prices add up. One thing I like is that for individual flights, they give the prices for different days around your preferred departure dates. Some days are dramatically cheaper than others. That might influence your travel dates if you have any flexibility.

It appears that there is no way to check both the return from a different city and the Icelandair Stopover option at the same time. But, I discovered that if you do the following you can get what you want at what seemed like a good price, at least for the test dates I used. All tickets would be purchased through Icelandair so if there are any issues, they will have to fix them.

Check: Icelandair Stopover.
From: SFO. To: London (All airports). Date: from the calendar.
Check: Outbound.
Click on: Next Step.

Your results should be the 3 major segments of the trip:
From: SFO. To: KEF. Date: the one you put in.
From: KEF. To: London (All airports). Date: put in the date you want to fly to London.
From: London (All airports) Change this to AMS. To: SFO. Date: put in the date you want to fly home.
Click on: Search.

Your results will be the three major segments of the trip and different price options. You can click on Show flight details for more details. Note that Icelandair doesn't fly direct from SFO. Other airlines operate the flights from SFO to the connecting airport. Whether you go on Alaska through Seattle or Jet Blue through an east coast city will depend on which SFO to KEF flight you choose. The same is true for the KEF to London options. What London airport you land at from KEF will depend on which flight you choose.

I hope this might work out for you. The price I got for my test dates (10 April, 16 April, 10 May) were about $1085 for one ticket. It might be higher in the summer.

Thank you, all, for the helpful, detailed replies. I really appreciate the tips and insight.

Wendy

Thank you, Tom! Very helpful!

If you want to skip the Iceland stopover, check out Aer Lingus. They fly from SFO to almost anywhere in Europe with a connection in Dublin. The prices are reasonable, and Aer Lingus is not as "bare bones" as airlines like WOW or Norwegian. Another nice advantage is that on the trip home, you can clear US customs and immigration in Dublin. On Aer Lingus, you could get a flight from SFO to London and a return flight from Amsterdam to SFO (multi-city option),