There are a few alternatives to traditional life jackets that are designed specifically for paddle boarding. One option is an inflatable PFD, which is lightweight and compact when deflated but provides buoyancy when inflated. Another option is a waist belt PFD, which can be worn around the waist and inflated manually or automatically in an emergency. However, it is important to note that not all alternatives to life jackets may be legal or appropriate for all water conditions, so be sure to check local regulations and safety recommendations before choosing an alternative.