The beaches on Harris are stunning and not crowded. Take a good wetsuit!
I also enjoyed Calgary (Mull) and Ostell Bay, which is far enough from the road to keep the numbers down. I cycled with the kids from Tighnabruich.
Can recommend the singing sands beach at Kentra, we seemed to arrive there by some off the beaten 'track' that nearly ended in a great peat sinkhole - but upside was that when we got to beach, it was at the far east end and simply beautiful. Don't know how to post pics but it's up there with the best.
The coral beaches at Culduie, just south of Applecross
What's made Achmelvich into a tourist trap? I can't imagine that it's been inundated by people selling tacky souvenirs but then I was last there in 2011 so perhaps it's all different now.
My parents have been having holidays there for the past few years (and back in the '80s when I was little too) and haven't mentioned it changing much. Except they were expressing concern that the static caravan site they use were putting up their prices due to receiving some big energy bill rises recently.
Also despite spending many summer holidays in the area I never realised that there was an actual Arisaig Beach! Which, according to Google is much closer to Morar than Arisaig. My holidays were at a camp site on the Back of Keppoch, there's some lovely beaches down there but they're all small (and the camp site I went to when I was young has now shut) so probably not so suitable for TJ's riding goals.
What’s made Achmelvich into a tourist trap?
Well, there's this thing called the NC500.
My favourite beach "at" Arising is Ben's Beach at Camusdarach.
What about Portobello beach? 😝
St Cyrus
Montrose
Lunan Bay
Crackaig Beach and Campsite, Sutherland.
😉
Ayr beach on the September Weekend?
Came on here to say Tiree but lots of others have already said it. Gott Bay for expansive views, Salum for seals, The Green for isolation, Balevullin for surfing and Hough Bay for otters.
Hynish pier a good spot for fishing from the shore (never failed to catch something there). Trip to the distillery worth it too (they do tours as well). And food at the Reef Inn is very good.
As you might have guessed I’ve spent a lot of time on the island over the years and can’t wait to go back (again).
riding on and between all Scotland's
This between bit.......all on your fat bike or are you allowed to cheat and use public transport too? If your 'all Scotland's' has them spread far and wide that could be some road miles on a fat bike. I know anything is possible and all that but I think that could do my head in. 99.9% of the trip's riding might be done on a very inappropriate bike so that the 0.01% is epic. I love my fatty(s) dearly but even the road rumble to the local woods is enough for me. I guess you'd be upping your pressures massively for the long (multi day) rides between the beaches which will help no end but still....
'Best' is always a bit subjective and unless it's your personal list might always feel like a woolly objective. How about Scotland's longest sandy beaches instead? That's where fat bike beach riding is so much fun. With maybe a compulsory camp on every beach ridden.
Glad my local beach Nairn made in onto the OP. I'm sure you know this already but the real magic there comes from riding from the Fisherman's Bothy to the West of Nairn all the way to Burghead with just the water taxi (and compulsory refreshment stop at the Captain's Table or Kimberly Inn) at Findhorn and a fiddle around marshes inside the old bar and Culbin Forest to break up an otherwise rather epic 35km of one way pristine sandy beach riding.
Don't forget the best mountain beach.

although you might want to avoid a bank holiday

In addition to the above… All of Colonsay’s beaches are nice. I like the Traigh Ban on the North east tip of the island. Other Traigh bans are available. Glen Batrick on Jura is lovely but off the beaten track a bit.
Crackaig 🤣
But only the SW end of it...
(BTW I hear that Crackaig might be up for sale as the owner is struggling financially)
St Andrews to Elie might be like the Lairig Ghru at bits where you on off on off constantly but a nice long walk although the grey North Sea is not a patch on the West coast
Arran see if you can circumnavigate it
Given the number of beaches mentioned it seems unlikely I will make it too them all. So I'll be trying to make a sensible ( ha!) route with the most beach to road ratio
The aim is to go light and bikepacking style and perhaps spend a month at it. 600ish miles seems very doable. I did 1000 miles a month last summer towing 18kg although mainly road / cycleways.
Aye - the fattie is a drag on road but I'm happy to bimble 35 miles a day. Not much in the way of public transport in the highlands. Distances are relatively short as well
Don’t forget the best mountain beach.
too close to Scotroutes 😉
You will be spoilt for choice Scotland has lots of wonderful beachs but you don't need a bike to explore them you need a sea kayak. Don't forget to go to Orkney and Shetland as there are many great beaches there. Just set off and follow your nose.
Crackaig 🤣
But only the SW end of it…
(BTW I hear that Crackaig might be up for sale as the owner is struggling financially)
He may have to expose all to a prospective new owner.
Will he be selling it at the bottom end of the market though?
As Pauly suggested, start on the East coast
Lunan Bay
Montrose
St Cyrus
could all be joined on to a Fife Coastal path start,North Queensferry to Broughty Ferry.
Discover the meaning of Fife 😆
North Coast - Reiss Sands, Dunnett, Thurso, Strathy, Reay, Torridale beach and loads more and all on the NC 500 route.....
Will he be selling it at the bottom end of the market though?
No idea, but I bet he applies for one of those beaver officer jobs.
Culbin Forest from Nairn to Findhorn and the Moray Coast Trail from Findhorn to Cullen plus there’s lots of nice tracks through the forest if you get bored with the beach.
I came here to say this, but its been mentioned a few times. I'll also never forget a trip to Iona. I was absolutely blown away by the white sands and turquoise waters, although the 327mph icy wind* did detract from the experience somewhat 😂 haven't got to visit any of the other islands other than Mull & Skye so far, but most are on my bucket list!!
*part of that statement may be exaggerated
Culbin Forest from Nairn to Findhorn and the Moray Coast Trail from Findhorn to Cullen plus there’s lots of nice tracks through the forest if you get bored with the beach.
It is ideal for most of us on STW:
[url= https://live.staticflickr.com/65535/52472257403_e33bffd4a7_k.jp g" target="_blank">https://live.staticflickr.com/65535/52472257403_e33bffd4a7_k.jp g"/> [/img][/url][url= https://flic.kr/p/2nWN32a ]Culbin Forest and Beach[/url] by [url= https://www.flickr.com/photos/matt_outandabout/ ]Matt[/url], on Flickr
I’ll also never forget a trip to Iona. I was absolutely blown away by the white sands and turquoise waters
Sounds familiar:
[url= https://live.staticflickr.com/65535/51999254153_f81fcdeeec_k.jp g" target="_blank">https://live.staticflickr.com/65535/51999254153_f81fcdeeec_k.jp g"/> [/img][/url][url= https://flic.kr/p/2ndZLCH ]Hebrides 2022[/url] by [url= https://www.flickr.com/photos/matt_outandabout/ ]Matt[/url], on Flickr
[url= https://live.staticflickr.com/65535/51999729205_93cb980f95_k.jp g" target="_blank">https://live.staticflickr.com/65535/51999729205_93cb980f95_k.jp g"/> [/img][/url][url= https://flic.kr/p/2ne3cRg ]Hebrides 2022[/url] by [url= https://www.flickr.com/photos/matt_outandabout/ ]Matt[/url], on Flickr
[url= https://live.staticflickr.com/65535/51999454029_111a60ac9c_k.jp g" target="_blank">https://live.staticflickr.com/65535/51999454029_111a60ac9c_k.jp g"/> [/img][/url][url= https://flic.kr/p/2ne1N3R ]Hebrides 2022[/url] by [url= https://www.flickr.com/photos/matt_outandabout/ ]Matt[/url], on Flickr
although the 327mph icy wind*
See also Crakaig - the naturism thing is probably an elaborate hoax. Wonderful campsite, hope we don't lose it.
Just browsing as I’m planning a trip over the border in May. Gigha is on the cards and Aran.
Araisaig is gorgeous.
Simisary beach is absolutely stunning, was little known but not so much now.
Berneray, between N Uist and Harris has a stonking bunkhouse with an endless unspoiled beach just to the west. The Harris west coast beaches are all good; Northton, Scarista etc. Luskentyre is the most popular due to the views to Taransay and much TV exposure but is huge and can take a few visitors. Huishnish is fine but there's a smaller, harder to reach, one a mile north of there that's unspoiled and has views to Scarp. Lewis has quite a few belters, mostly on the west side but Traigh Mhor at North Tolsta faces NE and is less exposed.
I think some of these would be great for riding a bike on e.g. Berneray west coast and others would be great to visit on a bike e.g. Tràigh-stir near Hosta (N Uist), There's a difference
On the Outer Hebrides, the fat bike would be nice for easy paths and tracks and for when the paths run out e.g. I reckon you could do a fair bit of Cladach Chairinis to Eabhal walking route after a dry spell on a fat bike
Kiloran Bay and The Strand on Colonsay are worth a visit.
and Machir Bay is awesome, followed by a visit to the Kilchoman whiskey place.
Gearaidh beach at Tolsta Lewis.
Ardtoe in Moidart.
May. Gigha is on the cards
I've just been chatting to Mrs_oab about the Coronation weekend - and a tent on Gigha, weather dependent...
Lunan bay on the east coast not been mentioned
St Cyrus whilst your there. Go and see Steptoe…
Berneray, between N Uist and Harris has a stonking bunkhouse with an endless unspoiled beach just to the west.
It's a good one.
[url= https://live.staticflickr.com/65535/52623934668_bee2681d02_k.jp g" target="_blank">https://live.staticflickr.com/65535/52623934668_bee2681d02_k.jp g"/> [/img][/url][url= https://flic.kr/p/2obcqoq ]DSCF0297[/url] by [url= https://www.flickr.com/photos/195076882@N06/ ]Rob Allen[/url], on Flickr
For a bit of variety - the coral beach near Dunvegan
On the East side, Culbin, Findhorn to Burghead.
Most of the others have been mentioned.
Mingulay beach, not really worth taking a bike though...
the naturism thing is probably an elaborate hoax
Ardeer is missing from the list so far 🙂

Nude beach in Scotland? Brrrrrrrrrrrer.
Im usually dressed in full mountaineering kit
TJ happy to join you for a loop of Coll or Tiree by fatbike (need an excuse to get over there) or if fancy exploring some of the ones on Mull
Can you still camp in the site on top of the cliffs at sango bay? Almost perfect there- great sand, surprisingly sheltered, caves and streams and rocks.
Some lovely stuff around tentsmuir, any time you get pine woods by the sea is OK by me.
TJ happy to join you for a loop of Coll or Tiree by fatbike (need an excuse to get over there) or if fancy exploring some of the ones on Mull
Probably the best place I have ever ridden a bike. Fatbike Heaven.
Sounds good.
Baleshare, west of Uist via the short causeway. I’ll be amazed if you see another person on it.
I’m ‘fairly sure’ no one has mentioned sandwood bay yet. The four and a half mile walk/cycle in is more than worth it.
