The changes which launched today will see the number of trains increased on some routes, meaning there is more space available on-board - particularly at peak times as people return to the railway.
Train services director for Southeastern Scott Brightwell said: "We’ve seen an increase in demand, and so we’ve added a number of additional and longer trains to our service.
"We’ll continue to review our passenger numbers and we’ll adjust train lengths and times where necessary.
"As government restrictions ease, we’re looking forward to welcoming more passengers back to travelling with us."
He added passengers can check how busy their train might be with the SeatFinder tools, and check which journey is best by downloading the Southeastern app or by checking live departure boards.
"We’re also asking our passengers to wear a face covering in crowded spaces, out of respect for others," he said.
Southeastern is also encouraging passengers to use The Key - a contactless smartcard - to fast track through the station and avoid the queues.
The Key enables passengers to buy and download tickets at home on the train operator's website or the Southeastern app - and can be ordered online.
Here is a summary of the changes:
Chatham Main Line
The 06:46 Dover Priory-Medway Towns-London Cannon Street service is reinstated
The 08:41 Gillingham-London Cannon Street service is reinstated
The 18:41 London Cannon Street-Medway Towns-Dover Priory service is reinstated
The 09:30 Faversham-London St Pancras is reinstated
The 14:25 London St Pancras-Ramsgate will terminate at Faversham
The 14:10 London Victoria-Dover Priory will divide at Faversham. The rear portion of the train will continue to Ramsgate
The 23:40 London Victoria-Ramsgate is added as an additional service (previously this was the 00:10 London Victoria-Ramsgate)
During off-peak times on weekdays and at weekends, the general pattern of the train service is as follows:
1 train per hour (tph) London Victoria-Ramsgate (semi fast)
1tph London Victoria-Dover (semi fast)
1tph London Victoria-Denmark Hill-Gillingham (stopping service)
1tph London St Pancras-Ramsgate High Speed service
The Faversham to Dover service remains hourly off peak, while the London St Pancras to Faversham services do not run off peak
Maidstone East Line and Medway Valley Line
The 08:55 London Victoria-Maidstone East-Ashford service is reinstated
The 18:57 Ashford-Maidstone East-London Victoria service is reinstated
The 19:34 Strood-Maidstone West service is reinstated
The 20:04 Maidstone West-Strood service is reinstated
Southeastern Main Line
Southeastern Main Line services to London Cannon St via Headcorn at peak times are reinstated. These include the:
06:01 Dover-London Cannon Street
07:15 and 07:38 Ashford-London Cannon Street
08:23 Tonbridge-London Cannon Street
16:30 London Cannon Street-Tonbridge
17:30, 18:02 and 18:30 London Cannon Street-Ashford
The 06:22 Tonbridge-Deal-Ramsgate is extended to Margate to give a through service from Deal and Sandwich to Broadstairs and Margate (Broadstairs College and the QEQM Hospital at Margate).
The 08:40 Margate-London Charing Cross is an additional service calling at Deal to fill a 90 minute gap in direct trains between Ramsgate and Dover and an additional first off peak train from the Headcorn line to London.
An additional service at 15:24 will run between Dover, Minster and Faversham to provide a through service for school pupils from Sandwich to stations on the North Kent Coast
The 13:40 London Charing Cross-Ramsgate will now run direct between Sandwich-Ramsgate
Many services between London Charing Cross-Ramsgate via Deal will wait at Dover to provide a connection with High Speed services to or from London St Pancras to reduce the journey time.
The 10:10 (and hourly until 14:10) London Charing Cross-Ashford International services are reinstated.
The 11:02 (and hourly until 14:02) Ashford International-London Charing Cross services are reinstated.
The 20:10, 21:10, 22:10 and 23:10 London Charing Cross-Ashford International services are reinstated to fill a 45 minute gap in service between London-Sevenoaks-Tonbridge and reinstate the half hourly service in the evenings through Headcorn.
The 19:02, 20:02, 21:02 and 22:02 Ashford International-Headcorn-London Charing Cross services are reinstated.
Hastings -London Cannon Street services at peak times are reinstated. These include the:
05:28 Hastings-London Cannon Street
06:30 Hastings-London Cannon St (non-stop between High Brooms-London Bridge)
17:00 London Cannon Street-Hastings
18:00 London Cannon Street-Hastings (non-stop between London Bridge-High Brooms)
09:21, 09:51 and 10:21 Tunbridge Wells-London Charing Cross (first off-peak)
09:00, 09:30 and 10:00 London Charing Cross- Tunbridge Wells
15:00 London Charing Cross-Tunbridge Wells.
The 05:40 Hither Green-London Charing Cross starts back from Crayford at 05:22
The 05:55 Crayford-London Charing Cross is added as an additional service.
The 06:35 and 07:35 Gravesend-London Charing Cross are additional services (not calling at Mottingham or Lee)
The 06:55 Strood-London Charing Cross is an additional semi fast service
The 22:48 Gravesend-London Charing Cross will now terminate at London Bridge
The 15:02, 15:32, 16:24, 19:32, 20:02 and 20:32 London Charing Cross-Dartford are additional semi fast services.
The 16:54 and 17:27 London Charing Cross-Gravesend are additional semi fast services
The 17:35 and 19:35 Gravesend-London Charing Cross are additional semi fast services
The frequency of trains on the Sidcup line at the busiest peak times is increased to 8tph, while during busier off-peak times the frequency is 6tph.
The 06:47 London Cannon Street-Slade Green is an additional service
The 07:39 Slade Green-Greenwich-London Cannon Street will start back at Bexleyheath.
The 07:18 Barnehurst-London Cannon Street starts back at Dartford at 07:08.
The 08:14 and 08:44 Barnehurst-London Charing Cross are additional services.
All evening peak services from London Charing Cross-Bexleyheath-Dartford will be formed of 12 carriages (from 16:27 onwards)
05:15 and 05:45 Hayes-London Cannon Street are additional services
The 0522 Hither Green-Cannon Street service is withdrawn
The 05:24 and 05:54 Hayes-London Charing Cross services will start at 05:30 and 06:00 and will no longer call at Lewisham
The off-peak and evening services from London Charing Cross to Hayes are reinstated, restoring the Hayes line to 4tph at off-peak times.
The 07:00, 07:30 and 08:00 Hayes-London Charing Cross services will start 2 minutes earlier. These trains will be formed of 12 carriages.