Geyser 1 captain Matt Collier said his side was looking forward to the competition.
"With us winning the title before Christmas our eyes are now set on the reserve grade competition that starts on February 1, but we want to take confidence from [the T20 tournament] into that reserve grade comp," he said.
Collier said his team had the ability to score a lot of runs quickly and should perform well today.
The club's second team is a very young side, the Geyser Fossils.
"The Fossils are full of Year 9 and 10 boys ... we thought rather than defaulting we would give these young guys some cricket," Collier said.
He said it was a good format for the young players to get a taste for senior men's cricket.
Collier said T20 provided a good atmosphere and some down-to-the-wire cricket, so it should be a good competition.
The first pool includes Geyser 1, Eastern Pirates, Taupo Combined Colleges and Taupo Old Boys.
The second pool includes Rotorua Central, Taupo Wanderers, Rotorua Indians and Geyser Fossils.
Premier Baywide cricket starts up again next weekend with the first round of the Williams Cup.
Local clubs Rotorua Central will host Mount Maunganui and Bay of Plenty Indians will host Element IMF Otumoetai Cadets.
Rotorua/Taupo senior reserve grade T20 competition today (starting from 12.30pm, Owen Delany Park, Taupo):
Round 1:
Geyser 1 v Taupo Combined Colleges, Eastern Pirates v Taupo Old Boys, Central v Geyser Fossils, Bay of Plenty Indians v Taupo Wanderers.
Round 2:
Taupo Combined Colleges v Taupo Old Boys, Geyser 1 v Eastern Pirates, Central v Bay of Plenty Indians, Taupo Wanderers v Geyser Fossils.