However, the dress codes in Batam are more relaxed. It is accepted that visiting Bule men often will wear short pants and t-shirts suited to the hot climate and Western style low cut jeans with short tops and exposed midriffs are now standard dress for many young local women. It is not entirely uncommon to see some girls wearing shorts in public.
However, if you are going to see an official or wish to enter a public office men will be expected to wear long pants and may not even be admitted in shorts. If admitted then the style of dress will be seen as a mark of disrespect or ignorance.
Due to the nature of climate in Batam, you need light clothing and will not need coats. Many visiting Western men wear shorts and this is acceptable.