If you're look to purchase a particular Apple Watch model at launch you should make an Apple Store reservation or pre-order online. Since there are a number of different models, inventory will be very limited at launch and availability for walk-in purchases will be very tight.
As one source at a flagship Apple Store said, “we’re told to treat launch day as if there will be no walk-in stock.” That doesn’t necessarily mean there will be absolutely zero Apple Watch units to buy at launch if you don’t have a reservation, just that the specific Apple Watch variant a person wants will be far harder to come by at launch than some previous iPhone models.
Inventory will vary depending on store location but we strongly recommend pre-ordering the device. Pre-orders start on April 10th. Customers will be able visit Apple Stores to try on the device starting April 10th as well. Try-on appointments will last for approximately 15 minutes and customers are advised to make a book a time for that if possible.
Sources say that the Personal Pickup service that lets you order online and quickly pick up at the store will be unavailable for the time being. That may change as more inventory becomes available.
The watch will officially launch on April 24th in nine countries.
Apple has already started approving apps with Apple Watch support which users will presumably be able to try out on April 10th. You can follow iClarified on Twitter, Facebook, Google+, or RSS for updates.