Turkish railways’ web page on international trains (currently only works with VPN) still says that all their international trains are temporarily stopped because of the coronavirus. Nobody knows when they will start again.

Forget this train for a few yrs to come. The complete line to border will also  be completely renovated (long overdue anyway) and built to new hi-speed standd and eletrify etc. TR has done that with a few other lines, but the money has run out and demand for this line is except the odd train-loving tourist minimal.If you plan more: check set61.com, has info on overlandd travel fromUK to all EUR countries and also for local trains. But DO read it all the way to the end to see the updates!

Night trains Sofia - Istanbul - Sofia will run again from 25.04 Istanbul 22.00 - Sofia 09.35 and from 26.04 Sofia 18.30 - Istanbul 07.00.

Also they say that from 03.06 direct connection Bucuresti - Istanbul will be restored.

Translate with Google : 

https://www.economic.bg/bg/a/view/noshten-vlak-otnovo-shte-pytuva-po-marshrut-sofija-istanbul

I am currently in Bucharest and was told at the counter that the night train from bucharest to istanbul will leave starting june (as you mentioned). Are you sure there is a night train active now from sofia to istanbul? Because then i eill go there :) 

Sofia - Istanbul will start on 25 April:

https://www.bdz.bg/en/a/sofia-istanbul-sofia

Timetables at the bottom of the page (links to the PDFs).

So-today not yet, wait a few more days,. Its a TR train, so from SOF only 1 day later toward IST. DO doublecheck In Turkey from which station it starts and how to get there on time to reach it-it will certainly not be the old Sirkeci anymore. You have to pay for a (very cheap) metro/tren ticket to get to that stop. And probably also get a local chipcard, which may cost much more.

I could get in the tcdd tasik…. site yesterday eve, but the info is only in Turkish-the /en/ would not work. There was a big sign extolling this new service.  More info also on seat61.com, the old routine

Thank you very much for the timetable. It will fit our schedule very well! Thank you!!

I took this train today, works fine. Go get your ticket at Halkali station, just show your pass at the ticket selling point. I had to pay the reservation for the couchette (15€). 

Hello! 

I want to book a night train ticket from SOFIA to HALKALI (ISTANBUL) but on interrail website, it says: 

Seat reservations unavailable

It seems no price offer is available right now. It is possible that all pass holder seats are sold out. Please check 'More information' and try other ways to book this seat reservation, or buy a separate full fare ticket to board. You need to buy a seat reservation to board.

Is there any other ways to book a couchette in this train outside interrail website? I don’t find this journey on Bulgarian State Railways (website of the rail company). 
Is the only option to get a couchette is to buy a ticket directly at the Sofia’s train station? 
Do you think tickets will be available if I’ll get one 2 days before leaving? I want to get one on 17th of July from 18:30 to 5:34.

Thanks for your answer,

Usually you are fine to book it in on the same day. With 2days in advance you have more than enough time.

I am on the same situation, should we risk to go to Sofia to buy the seat reservation on the station ? 

Should be no problem, certainly if you can do it a few days in advance.

This Monday I'll be in Sofia and I will try to buy a Train ticket for the same day and I'll tell you

I tried today to buy train tickets from Sofia to Istanbul and it's full for today and tomorrow. So expect to stay a few days if you don't have a ticket in advance. (Summer season)

Try to get it from Dimitrovgrad. The Bucuresti-Istanbul one usually has some empty places

Do you mean normal tickets or just the RES with a pass?

Basically it should be possible-it is on the normal BG/BDZ systems.

BUT do note that this really is a very big detour and the many direct buses will be much quikcer, more plentiful and probably also much easier to book. It may even not be that much more as just the surcharge for the couchette.

I would like to buy two tickets in ( 2 beds compartment Plovdiv-Istanbul) at Burgas station. 

Is there selling me international tickets?

So maybe better option will be buy ticket from Stara Zagora and take sleeping car from Bucarest to Istanbul

In Burgas can i buy international tickets for this connections??