When to purchase rail tickets

The Heathrow Express tickets are cheaper in advance, but they're valid for any train that day. So as long as your flight isn't delayed by 24 hours you're OK.

When we were taking overnight flights we used to buy the advance tickets from London but allowed 2-3 hours after the time we thought we would actually get to Paddington. (We are now lucky to have a daytime flight from Boston to Heathrow. We stay overnight in London and catch the train out the next day.)

You can see the discounts for advance purchase of Heathrow Express tickets here:

https://www.heathrowexpress.com/tickets-deals/prices-fares

Basically, the walk-up fare for tickets bought the day of travel is £22-£25, dependingnonnthe time of travel (off-peak is the lower fare).

Buy your tickets 90+ days ahead, and younwill,pay £5.50 for travel on weekends and bank holidayss, or £12.10 for weekday travel.

At 2019 prices, an Off-Peak Paddington to Exeter ticket is £73.40 bought on the day. That gets you on any off-peak train. Or buy an Advance ticket from about £20 and commit to a specific train.

Advance tickets are currently on sale for dates up to March

https://www.gwr.com/plan-journey/tickets-railcards-and-season-tickets/booking-tickets-in-advance

You don't have to buy in advance, or well in advance, but you save money if you do.

As you saw with the difference in the Exeter tickets, buying the train specific no-refund Advance tickets are as much as £50 per person cheaper. So you can plan to take the train several hours after arrival or (you say "we", so at least 2 people?) put the £100 towards a London stay for the first night and go down to Exeter when you have a day under your belts and can be sure of catching the specific train you have reserved.

Thanks to everyone for the great advice.

We won't be staying in London the first night, since I have already booked a hotel in Exeter.

I see that there are trains at 1404, 1504 and 1604 hrs.

Would I be safe to pick the 1504 that is four hours after we are scheduled to land at Heathrow?

www.nationalrail.co.uk

It appears there are plenty of trains via Paddington and one other station transfer. Prices are within 10 pounds of each other, and 2:40 to 3:5 duration. You can buy through links on this site or wait until arrival in Heathrow. I think the price will be higher if you use the Heathrow Express which tends to be costly compared to other rail services.

your flight is due to arrive at 11:05. I tend to allow 2 hours at Heathrow between touchdown and expecting whoever I am going to meet to come out of the frosted glass doors. So I'd expect you in the concourse by around 1pm.

Heathrow Express is 15 to 20 minutes depending on terminal and 4 times an hour most of the time, so allowing finding and walking time, possibly waiting 15 minutes if you just missed one and 20 minutes on board plus walking at Paddington and finding your train I'd allow an hour.

So, if you are on time and nothing goes awry you might at a push make a train at 2pm or so.

The 15:04 allows one hour beyond that. So you could have a one hour delay due to weather, congestion, being bussed to the gate, queues at immigration, waiting for slow luggage, etc., and just about be ok. Or stop for a meal, toilets, shopping for the train journey, etc.

That would be too tight for me, being aware of the consequences of missing it, but you may have a better tolerance for stress or be more lucky than I usually am, or catch a tail wind.

Don't dismiss the option of taking the Railair Coach to Reading station and picking up the train from there, especially if you are arriving at T5. Best time to book Railair is 2-3 months before your journey separately online.

I agree that the RailAir bus to Reading and a train from there would be a much better choice.

Thanks for the information on the Railair Coach to Reading Station.

It appears that the Reading Station is on the route from Paddington to Exeter (same trains as from Paddington to Exeter). Please confirm.

that is correct