The Welcome Walk is an event held annually by the university, wherein the incoming freshmen are welcomed by the university community and walk through the Arch of the Centuries, and head towards the Main Building. After that, they usually have a mass and an event where campus organizations and groups hold a sort of welcome party for the newly minted Thomasians. It is the university's way of linking their current students with their heritage and to create a certain rite of passage that binds all UST alumni.
Contrary to what you may think however, the Welcome Walk itself is not an age old tradition, and in fact dates back only to 2002, when it was simply known as "The Rites of Passage." Nevertheless, it is a new tradition that the university's community has taken to very well and looks to be a binding experience for their alumni for years to come.