Upvote:1
Here's what you should try: instead of trying to book a Singapore - London - San Francisco flight for outgoing and San Francisco - Singapore for return flight, book return flights from Singapore to London and then separate return flights from London to San Francisco.
I ran my search on Kayak.co.uk. I looked up PyCon 2012 dates you've linked to for a sample itinerary. For all options, I have taken Singapore outbound flight on 2 March, London outbound flight on 5 March, and San Francisco outbound flight on 16 March.
As you can see, by going for the second option you do save a bit. While it does mean it might increase your flight time, it's up to you to decide whether the savings are significant enough. Also, for the sample itinerary I chose, Emirates via Dubai came out to be the cheapest option for SIN-LON; for other dates, it could very well be Cathay Pacific via Hong Kong!
Upvote:3
I just did a quick search on kayak.com for tickets from SFO to Singapore and Singapore to London.
Based on one way fares for February 10, 2012. The 2 one way tickets through Singapore would be cheaper then flying from SFO to London directly.
So I will repeat the question I had. Do you really need to go to London first? I mean geographically it seems like such a backwards way to go.