The Philippines has humid weather, so you should wear something comfortable and breathable such as linen or cotton polo.
Also, wear light colors like white or nude to appear neat and decent. If you don’t have a polo, a plain shirt will suffice.
More importantly, avoid wearing shorts or jogging pants if you don’t want to look sloppy or unpresentable. Wear well-fitted denim jeans instead. In terms of shoes, I recommend wearing loafers or sneakers.
Remember, less is more. With a minimalist look, you will look elegant without much effort.
Related read: How to Dress in the Philippines
