Wales' preparations have been hindered by tournament-ending injuries to Matthew Rees, Gavin Henson and Morgan Stoddart, while there remains a major fitness concern over prop Gethin Jenkins.
Halfpenny, though, is back and in the World Cup selection mix after recovering from an ankle injury that meant a punishing rehabilitation programme to regain full fitness.
"It was superb to pull on the Wales jersey again," he said, following a promising return to action in Wales' World Cup warm-up win against Argentina. "It was always the goal to get back for the Argentina game, and there were no worries at all about the injury.
"We had about two or three occasions when we just had to take our foot off the gas a bit during the rehab because we had made such good progress.
"We got so far ahead of schedule that the ankle got a bit sore once or twice.
"So it was about managing it and then being able to go again. The main thing was being ready for the Argentina game, and there is no doubt it was ready."
Halfpenny promises to be a key member of Wales' World Cup squad, which will be announced on Monday by coach Warren Gatland, given his proven ability on the wing and as a full-back.
Despite not reaching his 23rd birthday until December, he already has 20 caps and additionally offers goalkicking back-up to the likes of James Hook, Stephen Jones and Rhys Priestland.
"If selected, the World Cup will be massive for me," added the Cardiff Blues player. "A few years ago when I was playing for Wales Under-20s, my mother showed me a book, and in there they had predicted the starting Wales team for the 2011 World Cup in New Zealand. My name was there.
"There is no way I could have dreamt that might happen. Now there is a possibility, and if it does happen it would be an absolute dream come true.
"Just for me to pull on the jersey again against Argentina was massive, so I've just got to wait and see what happens now."
And if Halfpenny is involved in Wales' World Cup opener against South Africa on September 11, recent rugby history between the countries suggests a tight, tense contest.
Wales go into the tournament after losing their last three home games against the Springboks, although only by a combined total of 12 points - 29-25, 34-31 and 20-15.
"My first game for Wales was against South Africa," said Halfpenny. "We were close on that occasion and we came into the changing rooms thinking we should have won.
"Then before the New Zealand tour last year, we got into the lead and let them back in. So, yes, it's a bit of payback, and there would be no better time than at a World Cup.
"We are probably in the best shape of our lives at the moment. We are just raring to go in New Zealand, and there is no reason why we can't go there confident we can win the group."
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