Under the agreement, the companies will sell wireless only to their own customers.
The two companies will only work together to approach any of the major wireless companies about MVNO (mobile virtual network operators) deals. They agreed that neither company will enter into any material transaction independently without consent from the other pending a year notice.
"By working with the team at Comcast, we can not only speed Charter's entry into the marketplace, it will also enable us to provide more competition and drive costs down for consumers at a similar national scale as current wireless operators," Charter Chairman and CEO Tom Rutledge said in a statement. "We look forward to working with Comcast through this innovative arrangement and bringing our focus on superior products and services, craftsmanship and quality customer care to the wireless space."
Disclosure: Comcast is the owner of NBCUniversal, the parent company of CNBC and CNBC.com.