In the last 8 years I have never had the need to use a pay phone.
Depending upon service provider, you can nearly always get a signal in the towns.
And usually on top of all the high hills.

I use Vodafone and it is pretty good in most of Scotland.

If you are not with Vodafone or a provider with good coverage, you could always just get a PAYG sim card and bung it in your mobile if needed.

As to Pay phones.
It all seems to be a bit hit and miss, so if you want to use them I guess coins and a card may be needed. You need someone with local knowledge for that.

There's definitely EE (Orange, T-mobile) reception in Braemar and Aboyne though 3G is a bit flaky in both places. I imagine Dalwhinnie won't be a problem as coverage all the way up the A9 is pretty good.

I understand that public phone boxes no longer take coins as it cost more to collect them than the coins collected. They work with credit cards.

I've had a right game with the few neglected phone boxes that are left. They are ill maintained and all but abandoned in most cases - just getting a dial tone has involved a lot of thumping banging and swearing. Then the b***dy buttons are sticky and fail to make contact. Aaaaargh!!!

In all honesty a couple of cocoa tins and a piece of string would be more use. The only telephone kiosk I ever use now is the one in the village ... which is used as a community library.

Take a mobile with a Vodafone sim is my advice!

Just before entering the Monadhliath in 2010, I sought refuge in a phone box. Hmmmm, there were fake posies and it was now used as a regional library and bulletin board but I was still able to make a phone call to Challenge Control with my credit card so all was good. In years since, I now buy a pay-as-you-go phone when I enter the UK for £10 or so (unbelievable good value!) for my 4 Challenge Control calls & occasional calls from Husband.

As for UK coins, they are much too heavy to be carrying 'cross Scotland. Generous tips (?!) are left in my wake. Ha.

Thank you everyone, just remains to ask whether anyone knows how O2 stands up in the Highlands? It would save having to buy a SIM card etc etc...
Cheers
Geoff

Vodaphone give the best coverage overal.

You can get a free Vodaphone SIM card by clicking on this link. Just top up when you need.

I'm Tesco Mobile, which is O2, I live in the Highlands aswell as being a Challenger, and I've always had a signal when I've wanted/needed one. Except in Culbin Forest...