Lauren Sager Weinstein, Chief Data Officer at TfL, has said it could be hugely beneficial to them in terms of having a "better understanding" of the flow of commuters at their busy stations across the British capital.
She said: "The benefits this new depersonalised dataset could unlock across our network are enormous.
"By better understanding overall patterns and flows, we can provide better information to our customers and help us plan and operate our transport network more effectively for all."
People who log into the WiFi network underground will have their data collected from July, following a four-week trial in 2016.
However, Privacy campaigners Big Brother Watch have warned that they need to ensure they inform their passengers that their data will be collected.
Voicing their concerns, a spokeswoman told the BBC: "We all should be concerned when our phones are tracked and movements monitored without our consent.
"The public should be fully informed about what data will be taken from their phones, when and why, and reminded of their ability to prevent this tracking by turning off their wi-fi."