Apart from when visiting temples, monasteries and pagodas, where you’ll need to dress conservatively, you don’t need to be concerned about wearing inappropriate clothing in Vietnam. If you’re visiting north of Hoi An between October and March, it can be cool so pack some layers. The rest of the year, and in the south, flip-flops or sandals, a cotton T-shirt and shorts are likely to be your daily uniform. We would recommend covering your arms and legs in the evenings to avoid mosquito bites. An umbrella will be useful to have as it’ll offer protection in both the hot and rainy seasons.