Before the COVID-19 pandemic, Bangkok was one of the most visited tourist destinations. Thus, an alternative tourist accommodation market has expanded rapidly especially on Airbnb platform. The number of properties listed on Airbnb reached 38,249 listings in 2019 with an annual average increase of 34% since 2015. Our previous study (2020) revealed that there was a possibility of rental housing market distortion from Airbnb in inner Bangkok because of the high presence of Airbnb to the number of households that rent the property for their accommodation, based on a city-wide study of Bangkok. This research aims at (i) investigating the conversion tendency of rental housing to Airbnb properties in the tourism-centric districts in inner Bangkok just before the Covid-19 pandemic and (ii) elucidating the socioeconomic factors and mechanisms that lead to conversion of rental housing to Airbnb. The study focuses on apartments and condominiums as they accounted for 83.4% of Airbnb listings by house-type in inner Bangkok. The results suggested that the ratio of Airbnb to rentals in the current market distribution (A-R ratio) indicated apartments had higher transformation tendency to Airbnb than condominiums. This is because (1) apartments are more favorable to conversion to Airbnb than condominiums in terms of the return of investment (ROI) metrics, (2) apartment operators are business entities that have the ability to manage their properties for Airbnb effectively, and (3) the condominium juristic person (CJP) prohibits unit owners to use their units for Airbnb in many complexes. Secondly, conversion to Airbnb is more prevalent in the city center because the area is more convenient for sightseeing and shopping than in the inner suburbs, especially for apartments. On the other hand, there is no uniform relationship between proximity to mass transit stations and the conversion to Airbnb, where distance from a train station does not necessarily indicate a clear distinction between rental housing and Airbnb locations.

The growth of peer-to-peer (P2P) accommodation sharing platforms, including Airbnb, has increased rent in the rental housing market in many tourism cities worldwide. Airbnb is also one of the biggest P2P accommodation sharing platforms in Bangkok. There were 38,249 Airbnb listings in 2019 in Bangkok, with an annual average increase of 34% from 2015-2019. On the other hand, many people in Bangkok still struggle with housing affordability and rental housing is one solution. To date, however, there has not been a study on the effect of Airbnb on the rental housing market.This research aimed to investigate an emerging situation and reveal the actual characteristics of P2P accommodation in Bangkok. The results suggested the following: (1) The growth of all Airbnb listings included an increase in inactive listings, which accounted for 47.4% of all listings in 2019; (2) Apartments and condominiums are the main property types listed, representing 72.1% of all listings; (3) The presence of active Airbnb listings is a small fraction (1.7%) of rental housing in Bangkok overall. Moreover, Airbnb listings tend to be concentrated in the Inner Bangkok of tourist spots, commercial and business regions, and high-end residential areas around the city center. Seven high-presence districts (more than 5%) and seven mediumpresence districts (2.5-5%) have emerged around these areas. Thus, they represent a risk for rental housing market distortion at the local level.