Big Bus Tours has snapped up the creator of the Go City Card, Smart Destinations, in a bid to grab a "larger piece of the global leisure marketplace".
Terms of the acquisition have not been disclosed, although it is understood to be in the region of $50 million.
Smart Destinations will become part of the UK-based BBT group, until now a provider of open-top sightseeing tours in 19 cities in four continents.
Go City Card was created to give visitors to a city the ability to access dozens of attractions from a single, online-purchased ticket.
The passes are available in 13 destinations in the US, as well as in London.
The acquisition is being heralded as an ideal opportunity for Smart Destinations to expand its network of cities around the world and for Big Bus Tours to secure its presence as primary operator of bus tours in relevant destinations.
Smart Destinations CEO, Ted Stimpson, says both companies are "committed to maximizing the in-destination experience of traveling consumers."
"Big Bus Tours is the perfect introduction to a city, guiding guests to the key places of interest. Go City Card passes provide a convenient and cost-effective way to pay for admission to those same top attractions.
"Together, we will deliver travelers to the gate and through the turnstile of the top paid attractions of the world."
Smart Destinations began life in 2003 as a web-based attractions pass platform, with a reported $40 million revenue by 2013.
Founder Kevin McLaughlin left the company in the September of that year and was replaced by Stimpson.
Laughlin is now CEO of Actourex, alongside the founders of Flextrip, Leith Stevens and Alex Kremer.