Advertisement AT&T Fiber Speeds Get Increased Quite A Bit, With No Extra Cost Advertisement Advertisement AT&T Fiber customers are in luck, as the company has decided to boost their internet speeds. The company has boosted speeds for entry and middle AT&T Fiber plans to 300Mbps and 500Mbps, respectively. AT&T Fiber speeds increased for entry and mid-level plans, with no extra cost So, just to be clear, the entry-level AT&T Fiber plan is getting an increase from 100Mbps to 300Mbps, while the mid-level plans will be boosted from 300Mbps to 500Mbps. Both plans are getting a 200Mbps boost, and there are no extra costs included.