A number of local iOS developer groups existed before Swift was created; they have since then been supplanted by Swift-specific groups. These will, of course, vary by geographic location, but a few meetup sites exist such as Eventbrite at http://www.eventbrite.co.uk and Meetup at http://www.meetup.com.

It is also likely that there are Twitter groups or meetups near you; for example, in London, there is @SwiftLDN at https://twitter.com/SwiftLDN who have regular meetings listed at http://www.meetup.com/swiftlondon/. In New York, the http://www.meetup.com/NYC-Swift-Developers/ group is fairly active. In San Francisco, both http://www.meetup.com/swift-language/ and http://www.meetup.com/San-Francisco-SWIFT-developers/ are active.