There are three means of transportation from Ubon Ratchathani to Bangkok When you want to travel.
Frist, you can go to Bangkok by train. Trains have three types such as free train, express train and sleep train. It is have seats comfortable. You need to check timetables before traveling every day. You should book tickets the counter. It takes about 10 hours.
Second, you can go to Bangkok by bus. Approximate price 600 baht.
The bus in ubon have many company such as Nakhonchaiair ,Sanguanchai and, Chanapai. It takes about 7-8 hours. You can book tickets the counter and online.
You can choose to sit as you like.
Third, moreover you can go to Bangkok by plane. Airlines include, Nok Air, Thai Lion Air, and Air Asia. Planes are more comfortable than the bus and train. It takes only one hour to travel. If you book the ticket before you travel for 1 week it will be cheaper. Approximate price 500 baht. You should study the details clearly before booking. You can book tickets the counter and online. It's comfortable, quick, and appropriate with people who don't prefer to travel for long times.
Lastly, means of transportation from Ubon Ratchathani to Bangkok you can go to Bangkok by train, plane, and, bus.