Whenever you order online, there is always a risk that specific clothing is not going to fit you properly. This is one of the disadvantages of ordering online. But, what is beautiful is some sellers and manufacturers will allow you to return their garments if the sizing is incorrect.
However, there will typically be a catch. Some sellers may mandate that the item still is in brand-new condition with the tags attached. So, before you rip the tags off, ensure that the swim parkas fit first.