The 737-700 was the first of Next Generation series when launch customer Southwest Airlines ordered the variant in November 1993. The variant was based on the 737-300 and entered service in 1998. It replaced the 737-300 in Boeing's lineup, and its direct competitor is the A319. It seats 126 passengers in a typical two-class layout or up to 149 in all economy configuration. Boeing launched the 737-700ER on 30 January 2006. All Nippon Airways was the launch customer, with the first one delivered on February 16, 2007. The 737-700ER is a mainline passenger version of the BBJ1 and 737-700IGW. It combines the 737-700 fuselage with the wings and landing gear of a 737-800. It offers a range of 5,510 nautical miles (10,205 kilometers), with seating for 126 passengers in a traditional 2-class configuration. A competitor to this model would be the A319LR. The 700ER has the longest range for a 737.
The 737-700C is a convertible version in which the seats can be removed from the aircraft to carry cargo. There is a large door on the left side of the aircraft. The US Navy was the launch customer for the 737-700C. The C-40A Clipper is a 737-700C used by the U.S. Navy as a replacement for the C-9B Skytrain II. The C-40B and C-40C are used by the US Air Force for transport of Generals and other senior leaders. The Boeing 737 AEW&C is a 737-700IGW roughly similar to the 737-700ER. This is an Airborne Early Warning and Control (AEW&C) version of the 737NG. Australia is the first customer (as Project Wedgetail), followed by Turkey and South Korea.
At the end of July 2008, Delta Air Lines took delivery of the first of 10 -700 model aircraft fitted with Messier-Bugatti's carbon brakes. All Nippon Airways, Japan’s second-biggest carrier, is to pioneer the models in Asia with a daily service between Tokyo and Mumbai. ANA’s service, believed to be the first all-business class route connecting to a developing country, was to start in September 2007 and use a Boeing 737-700ER outfitted with 36 seats and an extra fuel tank.