Within an hour or two, stock had sold out and delivery times were pushed back to June -- long after the April 24 date when devices were due to start shipping.
Many took to Twitter to complain. Some users said they would not buy the wearable as a result.
In a statement Thursday, Apple's retail chief Angela Ahrendts said the company will only take orders "exclusively online during the initial launch period" in order to maintain a consistent experience.
But demand appears to be high, considering the reviews were not all in the watch's favor.
"The watch is beautiful and promising -- the most ambitious wearable that exists. But in an attempt to do everything in the first generation, the Apple Watch still leaves plenty to be desired," said CNET senior editor Scott Stein in his hands-on review.