As an Czech citizen, you have two options to get a Vietnam visa no matter where you are. They are:
1. Apply for a visa at Vietnam Embassy (traditional way to obtain a valid visa for Vietnam)
If you select this option for visa application, you should contact the Embassy in advance to know the required documents you need to submit and procedure you need to follow since they vary from embassy to embassy. If not, it may take you more time and cost you much to provide full documents.
For contact information of Vietnam Embassies in foreign countries, please access to http://www.vietnam-visa.com/vietnam-embassy-information/.
2. Apply for a visa on arrival
This option requires you first to apply online for a visa approval letter via a travel agent. The letter is issued by the Vietnam Immigration Department officially allowing you to enter Vietnam and get visa stamped onto passport upon your arrival at Vietnam airport.
But please keep in mind that you can only use the visa approval letter if you enter Vietnam by air. It will be refused when you travel to Vietnam by land or sea.
For more information, please feel free to contact us.