The bank, a long-standing sponsor of England's one-day home international matches, will support Five's highlights of England's Test matches and limited-overs cricket throughout the summer.
NatWest's tie-up with Five will also include a bespoke online sponsorship package. The bank follows the Australian wine producer Wolf Blass, which backed Five's broadcasts of Ashes coverage last summer, as the sponsor of "Cricket on Five".
The deal was announced this week at a lunch for media buyers at which Five also revealed that the former England captain Michael Vaughan is to join its commentary team.
NatWest's media agency MediaCom brokered the deal with Rachel Wheeler, the sponsorship controller at Five. The new "Cricket on Five" sponsorship credits, created by M&C Saatchi, will launch on 22 June.