Is it necessary for my outward flight ticket to be within the initial 30 days in Thailand if I'm on a visa-exempt entry?

If you try to enter Thailand on a 30 day visa on arrival and your return flight is after the 30 day period, you may be denied boarding by your airline. I run a golf group in Pattaya and since covid airlines have been checking visas more thoroughly. Either get a TR ( 60 day ) visa before leaving or buy a cheap flight out of Thailand to somewhere like cambodia or similar.

As others have said, the tourist visa is the way to go. If you end up not getting it, extending for 30 days is easier than a border bounce.

I get the tourist visa in my own country because I try to avoid contact with Thai immigration. It's just less hassle and I don't waste half a day getting the extension done.

You can buy the 60 day SETV prior to deleting the USA Fir $40 for the Thai embassy/consulate in your region, you can then extend that for 30 days at your local immigration office for a cost of ฿1,900

You can arrive then after arrival you can extend it for a cost of ฿1,900 at your local immigration office for 30 days..if in Bangkok you can do it the same day as long as you meet the following requirements…arrive during normal business hours of the immigration office m-f minus holidays, hade your TM30 sorted and you can make it there before they close…other immigration offices have different policies on extension policies I.e: they won’t extend you until a certain number of days until your stamp expires

You can do 2 land border runs per calendar year (01 Jan - 31 Dec) which can be extended for 30 days at your local immigration office for a cost of ฿1,900

There is no official limit of air ins which you will get 30 days at a time with your USA passport which can be extended for 30 days at a cost of ฿1,900…caveat to air ins is that you will eventually be questioned by an overzealous immigration officer

There are so many low cost airlines in Thailand that it’s easy to buy tickets at cheap prices

Good luck

Get the 60 day tourist visa, problem solved.

If you want to minimize the risk, why don't you just apply for the tourist visa before you travel? It's cheaper than going to immigration and filing for an extension and you don't have to waste the day at immigration doing so. A tourist visa will give you 60 days in Thailand when you arrive.

If you travel without a visa you need to check with your airline. They are the ones who may require you to show proof of leaving Thailand within 30 days before they let you board your flight.