But he became unavailable for selection for the Springboks' first four Tests of 2010 - against Wales, France and the two against Italy - because he did not hold a South African passport.
The decision to exclude him from selection was taken following advice from the Ministry of Sport, reaffirming the government's position that no foreign player can be selected to represent a national team.
Mtawarira had been actively seeking South African citizenship and has now been granted that right by the minister for Home Affairs, Dr Nkosazana Dlamini-Zuma
"This is very gratifying news indeed and thanks to much hard work that has been going on behind the scenes over the past few months," the president of the South African Rugby Union, Oregon Hoskins told SARugby.com.
"It had long been the Beast's desire to become naturalised and he has had to endure some difficult times in recent months. He is now eligible for selection should he fit into the plans of the coach and national selectors."
Springbok coach Peter de Villiers wasted no time to welcoming his first choice loose head back into the fold as he named him among the 28 players he will use in the away leg of their Tri-Nations campaign which starts against New Zealand in Auckland on 10 July.
They then move on to the Westpac Stadium on 17 July before hopping across the Tasman to face Australia in Brisbane on 24 July.
De Villiers has included two players from overseas in Bath outside half Butch James and Ulster prop BJ Botha, but there is no place for Racing Metro utility back Francois Steyn at this stage.
Also missing, although through injury, are wing JP Pietersen, centre Adi Jacobs, scrum half Fourie du Preez, flanker Heinrich Brüssow, hooker Bismarck du Plessis and wing Odwa Ndungane. Juan Smith is ruled out for personal reasons.
"There is a very strong core of experience in this group and there are several leaders too. The new players who have come into the set-up this season are rewarded for their good performances," said De Villiers..
"We are very fortunate that we have several players who are versatile and can offer us options in different positions. The Tri-Nations is always tough and this year's tournament takes on added significance given that the World Cup is taking place in New Zealand next year.
"We have a tough start with successive matches against New Zealand, but we have had a good build-up and we have shown that we can win in New Zealand over the past two seasons.
Springbok Tri-Nations Squad
Backs: Gio Aplon (Vodacom Stormers), Juan de Jongh (Vodacom Stormers), Jean de Villiers (Vodacom Western Province), Jaque Fourie (Vodacom Stormers), Bryan Habana (Vodacom Stormers), Francois Hougaard (Vodacom Bulls), Butch James (Bath), Ricky Januarie (Vodacom Stormers), Zane Kirchner (Vodacom Bulls), Wynand Olivier (Vodacom Bulls), Ruan Pienaar (Sharks), Morné Steyn (Vodacom Bulls).
Forwards: Andries Bekker (Vodacom Stormers), Bakkies Botha (Vodacom Bulls), BJ Botha (Ulster), Schalk Burger (Vodacom Stormers), Jannie du Plessis (Sharks), Ryan Kankowski (Sharks), Francois Louw (Vodacom Stormers), Victor Matfield (Vodacom Bulls), Tendai Mtawarira (Sharks), Dewald Potgieter (Vodacom Bulls), Chiliboy Ralepelle (Vodacom Bulls), Danie Rossouw (Vodacom Bulls), John Smit (Sharks, captain), Pierre Spies (Vodacom Bulls), Gurthrö Steenkamp (Vodacom Bulls), CJ van der Linde (Vodacom Cheetahs).