Ryan Armour posted a 3-under 69 in the final round to finish a share of second place. He was joined at 6-under-par 282 by Nathan Green, who closed with a 70. Craig Jones and Greg Chalmers each posted final-round 71s to share fourth place at 5-under-par 283.
Bowditch, who held at least a share of the lead after every round, opened the final round with a three-stroke advantage. He extended that lead with an up- and- down birdie from just short of the green at the par-4 third. The young Australian jumped to 13 under with back-to-back birdies from the eighth.
The 21-year-old stumbled around the turn though. Bowditch struggled to a bogey on No. 10 at Royal Adelaide Golf Club, then faltered to consecutive bogeys from the 12th to slip back to 10 under.
Bowditch got one stroke back as he birdied the par-3 16th. He parred his final two holes for the easy win.
'Fantastic feeling. It all hasn't sunk in, I'm sort of lost for words,' said an elated Bowditch. 'I'm over the moon, that's about it. I just learned so much from Saturday. I was so nervous yesterday I didn't know what to do and I just learned so much from those first six holes out there. I really felt what I took in yesterday was a massive impact and it really got me through today.'
Armour tried to put pressure on Bowditch was a scorching front nine. He birdied Nos. 2, 3 and 5 to quickly jump to minus-6. He dropped in back-to-back birdies from the seventh as he posted a 5-under 32 on the front nine.
The 28-year-old Armour was derailed by a double-bogey five at the par-3 11th. He came back to birdie 15, but tripped to a bogey at the next to finish at minus-6.
Green also got off to a quick start with birdies at two and three. The Australian faltered to a bogey at the eighth, but turned around and birdied the ninth to make the turn at 6 under.
On the back side, Green bogeyed the 12th, but atoned for the mistake with a birdie on the par-3 16th. He parred out to share second place and finish as the only player in the tournament to post four rounds under par.
Australian Wayne Grady shared sixth place with Brandt Snedeker at 4-under-par 284. Brent Schwarzrock and Peter Fowler were one stroke further back at minus-3.
Cliff Kresge, who shared the first-round lead with Bowditch, closed with a 1-under 71. He was joined in 10th place at 2-under-par 286 by James Nitties (68), Peter O'Malley (70), David Smail (70), Chris Tidland (73), Greg Kraft (74) and Vance Veazey (71).