The Apple Watch arrived less than three months ago, and it's already shot to the top of the smartwatch market.

According to new data from Canalys, Apple shipped 4.2 million watches in the second quarter of the year, becoming the world's No. 1 wearable band vendor. Apple "easily" overtook Fitbit, China's Xiaomi, and all other smartwatch vendors, despite its watch's "significantly" higher price tag, the research firm said.

If it weren't for a few early hiccups, Apple could have potentially done even better. For starters, Canalys reckons that Cupertino missed a huge sales opportunity by launching its new watch after the 2014 holiday season. Secondly, supply constraints stalled shipments for the first few months after launch.

Still, "the Apple Watch is the most sophisticated smartwatch to date, and it has proved popular with Apple fans worldwide," Chris Jones, video president and principal analyst at Canalys, said in a statement.

But, he added, "Apple and other vendors still face important challenges to make the smartwatch a breakout hit. Improvements in performance, battery life, and sensor integration are needed to make future models more attractive, but it is the quality of third-party apps that will determine whether the Apple Watch will be a long-term success."

A color change might be first on the agenda. According to KGI Securities analyst Ming-Chi Kuo, Apple is prepping a gold-colored version of its Apple Watch Sport. Kuo, meanwhile, put Apple Watch sales at 3.9 million, which he characterized as "tepid," Business Insider reported.

Prior to the Apple Watch's release, a Reuters/Ipsos poll found that 6 percent of U.S. adults planned to buy the high-tech timepiece. Using 2014 Census projections, Reuters said that could translate into about 15 million Apple Watch sales, assuming folks followed through with initial plans for purchase.

Apple is holding its quarterly earnings call this evening, so we might get more details about Apple Watch sales then.