Comcast told Geekwire that it increased internet speed in Seattle four times over the last six years; it reportedly invested $1 billion in Washington to improve networks.
Brett Hamil, a local comedian, writer, and municipal broadband advocate, organized the upcoming event.
"We believe that broadband access is a social-justice issue and that Comcast and CenturyLinks' monopolies are a barrier to quality, affordable Internet," Hamil told Geekwire.
" target="_blank">posted a video on YouTube explaining the motivation for the walk.
"We're joining up for a slow internet walk ... to protest (Comcast's) abysmal service, sluggish (internet) speeds and sleazy business practices," Hamil said in the video.
At city hall, Hamil says the protesters will "demand our elected officials commit to building a municipal broadband network that will provide affordable and dependable internet service for all Seattleites, regardless of income or neighborhood."
On a map, the activists are walking about a 25-minute walk, depending on the lights.
Last summer, Seattle studied the feasibility of building and running a fiber network. The estimated cost was hundreds of millions of dollars.
Officials determined it was too risky and expensive. Costumers would have been charged $75 a month.