China Southern Airlines is taking delivery of their newest 737-81B today. B-5596 (c/n 38964, l/n 3700) is making its delivery flight from BFI to CAN (via HNL, MAJ, and SPN) as CSN218. From the HNL-MAJ leg on, the Puget Sound blog reports that the flight number changed to CSN596.
As noted, this is the 3,700th 737NG to roll off of the Boeing assembly lines. It's pictured above, on HNL's South Ramp, after it arrived from BFI, with a US Coast Guard HH-65B doing touch-and-go landings on Runway 4R.