• Hainan was part of Guangdong Province until August of 1988.
• On March 6, 1994, local phone numbers of Haikou (including QiongShan County) was changed to 7 digits. The rules are: 3x-xxxx to 53x-xxxx; 8x-xxxx to 58x-xxxx; 2x-xxxx to 62x-xxxx; 7x-xxxx to 67x-xxxx; 5x-xxxx to 85x-xxxx; 6x-xxxx to 86x-xxxx.
• Local phone numbers of Sanya and its vicinity was changed to 7 digits on July 13, 1996. The rules are: (Sanya) xx-xxxx to 8xx-xxxx; (Tongshi, Qiongzhong) xx-xxxx to 6xx-xxxx; (Ledong) xx-xxxx to 5xx-xxxx; (Baoting, Lingshui) xx-xxxx to 3xx-xxxx.

海口	898	Haikou (was 750)
琼山	898	Qiongshan (was 7691)
澄迈	898	Chengmai (was 8092)
琼海	898	Qionghai (was 7694, then 8096)
定安	898	Ding'an (was 8093)
文昌	898	Wenchang (was 7692, then 8094)
万宁	898	Wanning (was 7695, then 8097)
三亚	899	Sanya (was 7605)
通什	899	Tongshi (was 7684, 8001?)
琼中	899	Qiongzhong
乐东	899	Ledong
保亭	899	Baoting
陵水	899	Lingshui
洋埔	890	Yangpu
儋县	890	Danxian (was 7697)
儋州	890	Danzhou
东方	8003	Dongfang (was 7607)
昌江	8005	Changjiang (was 7608)