SOAP may also be used over HTTPS (which is the same protocol as HTTP at the application level, but uses an encrypted transport protocol underneath) with either simple or mutual authentication; this is the advocated WS-I method to provide web service security as stated in the WS-I Basic Profile 1.1.
Samuti on võimalik SOAP-i kasutada läbi HTTPS-i (rakenduskihis sama mis HTTP, kuid transpordiprotokoll on krüpteeritud) kas lihtsa või mõlemapoolse autentimisega; see on soovitatav WS-I veebiteenuste turvameetod, nagu väidab WS-I Basic Profile 1.1.