Best Route to Drive from Heathrow Airport to Mevagissey

While the M4 is a motorway , and less likely to have delays ( local traffic , farm vehicles , etc ) the A 303 will be a prettier , less grinding drive . Given similar timing , the A 303 is preferable ,

"the A 303 is preferable"
BUT the A303 often jams up by Stonehenge, I'm going on the M4/M5 tomorrow but only as far as Weston-Super-Mare, do this trip 4 or 5 times a year and would never dream of taking the A303 route. The M5 can be slow when joining from the M4 but it's not usually too bad.

And I always go to Devon & Cornwall on the M3 and A303, as it's more relaxing and with better views than going all the way by motorway, even with the jam at Stonehenge. Horses for courses I suppose.

Well, the majority is for taking the 303 it seems. I'm not sure what "horses for courses" means, but perhaps it means "each to his own?!" :) We are going to be driving on a week day–Thursday June 1– so perhaps the road won't be too busy? We'll be traveling during off hours too, as we pick up the rental car at 11 p.m. and hope to get to Mevagissey by late afternoon. Thanks all.....

"horses for courses" or as is said in French - " Chacun a son Gout "

Click this link & you will get a map of both the M4/M5 northerly route and the M3 / A303 southerly route between Heathrow & Exeter.https://www.google.co.uk/maps/@51.1385923,-1.9407603,9.63z/data=!5m1!1e1

I have enabled it to show live traffic with red indicating jams and orange = slow going. Now, if you bookmark it and return to it at various times of the day, you will able to see where the jams are occurring. (Things were pretty bad yesterday as it was a Friday preceding an extended holiday weekend - with the kids off school all next week).

You could go one way and return via the other route. I reckon that the A303 / M3 route is about 30 miles shorter than the M4/M5 route. However, parts of the A303 route are not dual highway. I would zoom in at various locations on the map - you can click & drag it - then click on the yellow man and place him on the road to see what it looks like. You can so the same with the 2 route choices that you have when west of Exeter = A38 to the south or A30 to the north.

Whichever route you take, I hope that you aren't planning this drive straight off a long flight.

The A303 is more likely to suffer traffic problems and jams, but is the more interesting option. Check with travel websites on the day of travel if there are any delays (such as theaa.com or trafficengland.com) or listen to the car radio for travel bulletins. Whichever, be prepared for the journey to take quite a bit longer than planned, as there are often delays.

We'll be traveling during off hours too, as we pick up the rental car at 11 p.m. and hope to get to Mevagissey by late afternoon.

So will you be driving all night? After a long flight? Please reconsider. Driving a long drive like that after a long flight is dangerous enough, not only to you but everyone else on the road - jetlag can make your reactions and reflexes like driving drunk - but it will only be worse going all night.

Have you considered taking a train from Paddington to St Austell and getting a car there, after several relaxing hours on the train?

Thank you everyone for the website suggestions and tips. Very helpful. After looking at a Michelin map we had from a previous trip to England, my husband definitely wants to take the M3-A303 route, so it's settled. He is an architect who loves looking at iconic buildings, so we might stop at Salisbury to see the cathedral there. We'll have to deal with whatever comes our way as far as the traffic goes! Fingers crossed! KW

Thank you everyone for the website suggestions and tips. Very helpful. After looking at a Michelin map we had from a previous trip to England, my husband definitely wants to take the M3-A303 route, so it's settled. He is an architect who loves looking at iconic buildings, so we might stop at Salisbury to see the cathedral there. We'll have to deal with whatever comes our way as far as the traffic goes! Fingers crossed! KW

Thank you Nigel, but we will not be driving after a night flight! That is far too risky as you say. We arrive the night before at 8:30 p.m. and will spend the night at a hotel near Heathrow.

Oh, I meant to say we pick up the car at 11 in the morning! I see why Nigel was concerned!

I think you should pick up the car earlier and certainly be on your way by 10am. Remember, that 5 hours is driving time. What with taking a detour into Salisbury - you won’t be driving continuously for 5 hours.

This place is just off your route:>https://www.nationaltrust.org.uk/montacute-house

Heathrow to Mevagissey is a long trip and I can’t see why you would delay departure until 11am.

If you want to go to Salisbury and are looking more for scenery than speed you might as well take the A30 from Sutton Scotney and not rejoin the A303 at all carrying on to Honiton. Yeovil can be a bit sketchy depending on the time you arrive but much of the rest of the route is quite good for a single carriageway, and eliminates the detour to- and from- the A303.