When you are planning to fish, kayak, raft and hiking into the wild, a waterproof duffel bag is worth considering. It has larger volume than the dry bag which can allow more gears and also it is the same waterproof as a dry bag.
Technically, there are two solutions to make sure no water enters your duffel bag. The first one is so-called roll top duffel bags, which is as the name suggests that you roll up the top of duffel bag and close by a buckle in order to get the water out of it. This kind of waterproof duffel bag makes sure no water can get in no matter how harsh the rain. The second kind of waterproof duffel bag is equipped with waterproof zipper, which even allow for the bag to be immersed into water without getting wet on the inside. But this kind of waterproof duffel bag is more expensive than the roll top type. There is also advanced type of waterproof zipper duffel bag that is the waterproof duffel bag with air tight zipper. This is the ultimate type. The air tight zipper can even block the air. Also this kind of waterproof duffel bag can be regarded as a buoy.
Conclusively, how to choose the best waterproof duffel bag depends on how you would like to use it. If you just want to kayak or camp a roll top waterproof duffel bag is quite enough. If you want to swim, dive or cross wild river a waterproof zippered duffel bag will be a better choice.
