How early do we need to be for train?

Doors close for boarding the train about 2 min. to 30 seconds prior to the train leaving. And many times yo won't be allowed to even go down the platform until about 10 min. prior to the time it leaves. Paddington is a rather large station. I'd allow at least 15 -20 min. to get to the central area where the board is which lists platforms, then get to your platform. That will also allow time for a bathroom break if urgently needed. So be at the station at least by 6:40. 6:30 is better if you want a 'comfort cushion'. That would also give you time to purchase some snacks or drinks for the train prior to boarding.

Not only are you not allowed onto the platform, they don't even list the platform number on the departure screens until 10-15 minutes before departure. So there is no real advantage in being early.
They say "doors may close up to 30 seconds before departure", but that is just to cover themselves.

Allow 5-10 minutes to walk in off the street, or up from the tube. I would aim to get to the station 30 minutes before departure.
It is a fairly simple station, open plan, one big concourse and all the platforms on the same level as the concourse. You can't get lost.

It all depends on where you are coming from, by what method of transport, what contingency you want to allow, and if you want to buy food and drink at the station.

Thank you so much, everyone! That's one worry off my list for tomorrow. I really appreciate your guidance.

As mentioned already it's pretty easy to find your track. Here's the the layout.

http://16cbgt3sbwr8204sf92da3xxc5m-wpengine.netdna-ssl.com/wp-content/uploads/2016/12/Paddington-Station-Map.pdf

I am really risk averse and am not as used to taking public transport as many here. I go for 45 minutes ahead and that gives me time to scope things out, make a comfort stop and grab something for a meal on the train.

You refer to a 7pm train to Bath, but there isn't one on 12 July.

There is engineering work this week around Chippenham, which means trains to Bath are reduced in number and at different times to usual.

There is one at 19:12. Expect it to be very busy as it is the first train in the evening where super off-peak tickets are valid.

Thanks, we have decided to go a little earlier, especially now that we've learned of the Paddington Bear shop ;)

@Marco, you are correct that our tickets are for the 19:12 train. Thanks for the heads up on the current changes. We will build a little more time into our schedule to accommodate a bigger crowd.

We already have seat assignments, so we don't need to worry about time management and and not about getting a seat?

Thanks!

ck

Depending on where you are going to Paddington from, be aware that there is a significant Formula 1 event in and around Trafalgar Square today and this evening which may play havoc with surface transportation in and around that part of town. Tubes should be unaffected other than the usual rush hour crush.

Enjoy the nice weather. When the clouds and drizzle burn off in a couple of hours it is scheduled to be a nice day today.

Thanks, I think we saw the set up for that yesterday in Trafalgar Square but didn't know what was going on. Off to St Paul's and Tower of London!

Have a great day everyone, appreciate all of the help and guidance!

I would get there an hour earlier and have one of the superb cocktails in the gorgeous Gilbert Scott https://www.thegilbertscott.com/bar/

I can't think of a more pleasurable way to start the journey to Bath!

Although if you have seat arrangements you should be OK, the immediate post 19:00 trains to all destinations from Paddington are crowded. More so to South Wales and the South West and even more so on a Friday, but nevertheless I suggest getting on as soon as it is announced in case it is later standing room only, just to be sure of getting to the seats comfortably.