Thameslink train schedule change

The only train that goes directly to St Pancras from Gatwick is Thameslink. Southern goes Gatwick to Victoria where you can catch a Victoria Line Tube train to Kings Cross St Pancras. Gatwick Express also goes Gatwick to Victoria where you can catch a Victoria Line Tube train to Kings Cross St Pancras.

Take Thameslink.

Are both of your trips Gatwick to St Pancras Intl or is one of them the opposite direction?

Where are you looking for the timetable?

I have a return ticket : Gatwick to St Pancras , St Pancras to Gatwick. I went to "Timetables from 20 May 18", from there it sends me to Railplan20/20 Website. From there, there are two possible routes (I'm not sure which to look at), Thameslink (Inc to and from Great Northern), and Great Northern ( Inc. Great Northern Services). Neither makes any sense.

One would think that Thameslink would update the schedules on the site where one books a ticket.

The new timetable is being introduced progressively between 20 May and 8 June on the route from St Pancras to Gatwick Airport.

You can see the new timetable here under Horsham and Gatwick Airport to East Croydon and London (all Services). Look for the TL trains from Gatwick to St Pancras.

https://www.railplan2020.com/timetables/timetables-introduction

Trains are so frequent it isn’t worth worrying about.

i think I have it; thanks so much.

Thameslink and Great Northern were previously two separate rail service groups that are gradually merging both corporately and in terms of new linking tracks. Don't worry about the difference.