I've got a round trip domestic flight booked. Due to a change of plan I don't need the outward, but still want to keep the return leg. If I don't show for the outward will they automatically cancel the return? I know many airlines do this, but I couldn't find any reference to it in Air Asia's T+Cs. Anyone experienced this before?

To the best of my knowledge - each leg on Air Asia is standalone. I have booked 2 ways tickets on Air Asia several times and ended up using only one segment. So, your not showing for one leg, should not affect the next segment.

The situation you mention is very common with US carriers, especially within the Continental US. Opt to skip out a certain sector and they sometimes cancel all remaining coupons.

Why not afford them the common courtesy of phoning and letting them know in advance you're going to be a "no show"? Then you can confirm it has no effect on your return leg and let's them re-sell the seat.

Good Luck. All I ever got from them on the website is to buy more insurance that I didn't want. Try calling them. If you get through you will be passed around a lot.

I honestly don't know the answer to your question, but it can not be emphasized enough that it is actually NONSENSE to book return flights on no-frills-airlines when you can book the same flights as one-ways without any extra costs.

this gives you much more flexibility.

why don't you call AirAsia directly. their Thai call center is usually friendly and useful (as long as you don't act like a Farang ting-tong from the first second)

ll I ever got from them on the website is to buy more insurance that I didn't want.

They ask you if you want or not the insurance. Just read carefully the message appear on the web page. I never have paid that insurance.