My visa date of propose arrival is March 15 can i arrive in Vietnam before that date?
Be kindly informed that you CANNOT enter Vietnam before the arrival date granted in your visa approval letter. In case you wish to enter earlier, you should apply for a new visa approval letter. You are now offered two way to apply for Visa: Applying for Visa on arrival (VOA) and Getting visa at Vietnam Embassy in Spain. If your want to promptly get Vietnam visa as you planned to enter Vietnam earlier, applying Vietnam visa online from Spain is an ideal option.
In case you are Spain passport holders, you can apply for VOA to Vietnam. Otherwise, you have to check whether you are required a visa to Vietnam or not and check Vietnam visa requirement online to make sure that VOA is applicable to your nationality.
Wish you all good things.