The Scotsman, who took over from Sir Alex Ferguson this summer, has been linked with a host of big names this summer but has so far only signed young Uruguayan defender Guillermo Varela.
A summer-long pursuit of Barcelona's Cesc Fabregas came up empty while another Barcelona target, Thiago Alcantara, opted instead to join Bayern Munich.
Most recently Moyes has been linked with a double raid on former club Everton for Marouane Fellaini and Leighton Baines while Real Madrid's Luka Modric has also been repeatedly linked.
"I'm confident we'll have players in before the start. We're involved in discussions for several players, and we're working very hard to do so," Moyes told Sky Sports.
"It was always going to be a difficult window for me personally. I joined on the 1st of July, which has given me a short period.
"It's never the same until you've worked with the players, but we've got a great group of players, they won the Premier League last year."
Moyes also again reiterated that Chelsea target Wayne Rooney is not for sale.
"There have been no more developments. We don't want any more developments. We've said he's not for sale," Moyes said.
"I'll see how he is (for Swansea on Saturday) when we get back. We'll assess him. I watched the England game and I thought the 65 minutes he did he played well, he ran around and got some fitness. It's the first real action he's had."