Hainan visa on arrival.

I'm honestly always in favor of 30 day visa free access, but since your wife is an Ecuadorian citizens and consequently not eligible for this option and since you will fly from Hong Kong, here are the guidelines for your successful trip:

Citizens of countries or regions with diplomatic or trade relations with China are eligible for the visa on arrival when arriving in Haikou or Sanya. With the visa on arrival, you can travel to any part of China for up to 15 days total, and leave China from anywhere!

Visa on Arrival Process:

1. Before you travel, call the hot line of Hainan Exit-Entry Inspection and Quarantine Bureau to ask about the Visa on Arrival eligibility for your nationality.

Haikou Meilan Airport Visa Office Number: +86-898-65751994

Sanya Phoenix Airport Visa Office Number: +86-898-88289566

2. After arriving at the airport, go to the visa section and get your visa. (24 hours service)

3. What you need to prepare: your valid passport, one 2-inch color photo without hat (on-site photography service available), visa on arrival fee (varies from 168 to 1,000 RMB, cash only). In your case, UK citizen will be 304 CNY and Ecuadorian 168, although I cannot confirm this with 100% certainty. You are advised to buy at least 2.000 CNY at one of Hong Kong money changers before your departure to Hainan.

4. After receiving your visa, you can travel to any part of mainland China, and stay for up to 15 days, to explore the country.

5. You will need to register with the local police station within 24 hours after arrival in each place you stay. If you are in a hotel, the staff will take care of this for you, but if you are camping or staying in a friend’s apartment or other location, you will need to go to the local police station with your passport to register. This is a national law.