Zimbabwe, who was knocked out of the senior competition at the first round stage, dodged the rain showers to dismiss Namibia for 193 and to set up a meeting with either Nepal or Bangladesh in Friday's final.
A successful tournament for Namibia, who caused a shock by beating Sri Lanka in the early stages of the competition, came to an end against a Zimbabwe side boasting three players with international experience at the senior level. Sean Ervine, who made his One-day International debut against England last October, claimed the man-of-the-match award for an innings of 72 that lifted Zimbabwe's total to 228 from its 50 overs.
Ervine's well-paced innings contained eight fours and a six and helped propel Zimbabwe from 86 for 4 past the 200 mark. Zimbabwe's two Test players, Tatenda Taibu (30) and Hamilton Masakadza (22), also contributed as did 15-year-old schoolboy Brendon Taylor, who made a responsible 37.
All-rounder Burton Van Rooi, who has had an impressive tournament, was the best of the Namibian bowlers with figures of 3 for 33. Namibia's innings got off to a poor start when Zimbabwean pace bowler Waddington Mwayenga had captain Stephan Swanepoel caught at second slip for eight and then bowled Hugo Ludik for a duck.
Van Rooi became Mwayenga third victim when he played across a straight delivery and was adjudged leg before for nine as Namibia lurched to 36 for 3. Michael Greef and Johan Nel added 31 for the fourth wicket but the dismissal of both batsmen within three deliveries dealt a fatal blow to Namibia's chances.
Greef was the first to go for 43 when he was bowled attempting to drive to long off and in the next over Taibu claimed Nel's wicket for 31 when he cut to point.
Namibia showed an admirable fighting spirit with Michael Durant hitting 48, adding 34 with Tobias Verwey (10) for the seventh wicket, and 30 for the ninth with Hendrik Geldenhuys (17).
Zimbabwe coach Steve Rhodes, the former England wicket-keeper, was disappointed that his side could not kill off its opponents after reducing them to 98 for 7 but was pleased with the end result. "Our ground fielding was disappointing and we took our foot off the gas," he said.
I was pleased with the way Sean Ervine batted. He dug us out of a hole at 86 for 4 and to get 228 from that position was excellent.
We were always in a very comfortable position and they were never really in with a chance." Rhodes said the team was now focusing on the final of the Plate event. "I would rather meet Bangladesh in the final simply because we have played them before and we know a bit more about them," he said.
"All I know about Nepal is that they are very well organised and its coach Roy Dias has done a good job with them.
Namibian coach Werner Jeffrey praised his team despite the semi-final loss, highlighting its three wins in the tournament. "I'm delighted by our performance in the competition," Jeffrey said.
"In the previous two World Cups we did not win a single match, but this time we have reached the semi-finals. "We obviously wanted to reach the final but I'm very pleased with the way the guys have performed.
This is a good stepping stone for these players and some of them are now pushing for selection for the senior team." Namibia now return home to begin its preparations for next year's senior World Cup, which several team members, including Swanepoel and Van Rooi, are expected to compete in.
Nepal and Bangladesh meet on Wednesday with Australia and the West Indies battling it out for a place in the final of the main competition on the same day.