Yes, you should be able to get this done. If it’s Test and Go you’ll need to upload your SHA+ hotel stays for days one and five, your vaccination records and flight information. Best of luck to you.
Recommend a Non-O applied for through your home country’s Royal Thai Embassy/Consulate. Arrive, deposit required funds in a Thai commercial bank for 60 days and then apply for 1 year extension. On going requirements will include 90 reporting (hopeful it’s on line soon) and annual extensions at Immigration.
You can do it anytime, and it runs from date of expiry of your initial 30 days. We recommend at least 5 days prior to expiry just in case something comes up.
This is out of my area of expertise, but I purchased a Pacific Cross policy from Darren at Seek2Insure.com. He was recommended by another member of this group. My personal experience is that he and the insurer were responsive and provided the docs I needed for entry. I did check with my hospital (BNH) and an admin there said they would accept the policy. If you have a hospital in BK, I would confirm acceptance of coverage before purchasing anything. Happy to hear from others on this subject.
Right now everyone entering the Kingdom needs a policy with coverage limit of at least US$50K, but at the moment does not need a specific Covid coverage certificate. We will see on or after January 4 what changes will be made to the current system. That’s the date announced by the PM for reconsideration of the current suspension of the Test and Go Program