With apologies for asking an often-asked question no doubt, the mother-in-law is winging her way here soon and her probable dates of stay may be about 40 days. I think the initial 30 days can be extended at the local (Chiang Mai) Immigration office .... and I presume she would have to turn up in person to do this, and that that could be a long day with no guarantee of being processed, given the chaos reigning there just now. Also not sure of the cost and how many days an extension would get her. Thanks in advance.

1900 thb and currently 30 days given on a 30 day visa exempt entry.

Better still, and cheaper, get a single entry tourist visa before leaving. That will also avoid issues with the airline on check-in.

Per above answer, getting a toruist visa would be easier and avoids possible trubles with the airline.

(Without a visa one needs to have proof of onward travel within 30 days of arrival).

I would also advise a tourist visa, valid 60 days... she doesn't want the stress of dealing with CM Imm (the congestion, that is), believe me!

In all fairness, the queue for the 30 day extension of visa-exempt entry is not the same queue as the one for retirement extensions. No need for Mum to arrive at 5 am at CM Immigration. I've seen the queue for 30 day extensions move quickly, with waits of a just a couple hours.

Could you do a run up to the border instead - maybe turn it into a couple of days trip and take in Chiang Rai?

Per above answer, getting a toruist visa would be easier and avoids possible trubles with the airline.

(Without a visa one needs to have proof of onward travel within 30 days of arrival).

This is never enforced. I fly in and out a dozen times a year and have never been asked for proof of onward travel.

Per above answer, getting a toruist visa would be easier and avoids possible trubles with the airline.

(Without a visa one needs to have proof of onward travel within 30 days of arrival).

This is never enforced. I fly in and out a dozen times a year and have never been asked for proof of onward travel.

'This is never enforced. I fly in and out a dozen times a year and have never been asked for proof of onward travel."

It may be seldom enforced, but it would be misleading to say it's never enforced. Some airlines can be sticky about it.

Per above answer, getting a toruist visa would be easier and avoids possible trubles with the airline.

(Without a visa one needs to have proof of onward travel within 30 days of arrival).

This is never enforced. I fly in and out a dozen times a year and have never been asked for proof of onward travel.

'This is never enforced. I fly in and out a dozen times a year and have never been asked for proof of onward travel."

It may be seldom enforced, but it would be misleading to say it's never enforced. Some airlines can be sticky about it.

Which airlines?

Per above answer, getting a toruist visa would be easier and avoids possible trubles with the airline.

(Without a visa one needs to have proof of onward travel within 30 days of arrival).

This is never enforced. I fly in and out a dozen times a year and have never been asked for proof of onward travel.

'This is never enforced. I fly in and out a dozen times a year and have never been asked for proof of onward travel."

It may be seldom enforced, but it would be misleading to say it's never enforced. Some airlines can be sticky about it.

Which airlines?

Jetstar at Sydney airport. I had to buy a return leg or they would not let me fly. That was in 2010.

Could you do a run up to the border instead - maybe turn it into a couple of days trip and take in Chiang Rai?

Agreed, a shopping-trip to Tackilek, combined with a visit to Mae Salong or the Opium Museum at the Golden Triangle mega-photo-opportunity-emporium would be an interesting solution to the problem, for many tourists new to Thailand.

Which airlines?

KLM, BA, Lufthansa, China Airlines, JAL, PAL, Emirates, Qantas, Thai Airlines, Qatar Airlines, Malaysian Airlines in the past two years and NEVER been asked for onward ticket.