The longest caves list is updated to 5 September 2026. It has all the caves that have been surveyed to a length of over 1,000m.
| No. | Name | Province | Length | Surveyors | Date |
| 1 | Tham Phra Wang Daeng | Phitsanulok | 13,789m | RFD/SMCC/OCC | 1997-2004 |
| 2 | Tham Lom-Tham Nam System | Chiang Mai | 13,541m | SpeleoDAO expeditions | 2015-2020 |
| 3 | Tham Mae Lana | Mae Hong Son | 12,720m | Australian expeditions/NEUA26 | 1986-1992/2026 |
| 4 | Tham Luang Nang Non | Chiang Rai | 12,390m | CMRCA/SMCC/BEC/Unsworth | 2014-2025 |
| 5 | Tham Yai Nam Nao | Phetchabun | 10,597m | SMCC | 2004-2014 |
| 6 | Tham Nam Lang | Mae Hong Son | 8,950m | Australian expeditions/D. Smart | 1986-1993 |
| 7 | Long Snake System | Mae Hong Son | 8,654m | Australian expeditions/NEUA expeditions | 1990/2024 |
| 8 | Tham Takobi | Tak | 7,346m | SMCC | 2000-2003 |
| 9 | Tham Chiang Dao | Chiang Mai | 5,669m | CMRCA/APS | 2021-2025/1980 |
| 10 | Tham Krachaeng | Yala | 5,633m | L. Price | 1993-2000 |
| 11 | Tham Nam Wang Si Thamma Sokarat | Nakhon Si Thammarat | 5,400m | P. Ashwell | 2011-2014 |
| 12 | Tham Pha Phueng | Nan | 5,180m | SMCC | 2005-2023 |
| 13 | Tham Pha Daeng | Chiang Mai | 4,703m | CMRCA/SMCC | 2005-2026 |
| 14 | Tham Ban Nam Mut | Kanchanaburi | 4,461m | CSCA | 1992 |
| 15 | Tham Khang Khao | Phitsanulok | 4,172m | RFD/CSS/SMCC/OCC | 2003-2023 |
| 16 | Tham Pha Mon | Mae Hong Son | 4,050m | APS | 1985 |
| 17 | Tham Sua-Tham Lom System | Mae Hong Son | 3,631m | D. Smart et al./SMCC | 1993/2026 |
| 18 | Tham Le Stegodon | Satun/Trang | 3,389m | DMR | 2017 |
| 19 | Tham Tukkatan | Chiang Mai | 3,160m | CMRCA | 2021 |
| 20 | Tham Din Phieng | Nong Khai | 3,102m | Clubul de Speologie "Z" | 2024-26 |
| 21 | Tham Phra Sai Ngam | Phitsanulok | 3,026m | RFD/CSS/SMCC | 1997-2018 |
| 22 | Tham La-ong | Nan | 2,969m | SMCC | 2019 |
| 23 | Tham Nam Mut | Kanchanaburi | 2,938m | CSCA | 1992 |
| 24 | Tham Phu Khieo | Chaiyaphum | 2,866m | British expedition | 1989 |
| 25 | Tham Nam Tok | Kanchanaburi | 2,710m | CSS | 1996 |
| 26 | Tham Susa | Mae Hong Son | 2,646m | Australian expeditions | 1992 |
| 27 | Tham Huai Lao Pu | Tak | 2,625m | SMCC | 2002 |
| 28 | Tham Phu Pha Phet | Phatthalung | 2,445m | DMR | 2018 |
| 29 | Tham Wang Mu | Trang | 2,422m | SMCC | 2024 |
| 30 | Tham Maa/Tham Yang | Nan | 2,371m | SMCC/BEC | 2016-2018 |
| 31 | Tham Nok Nang En | Kanchanaburi | 2,340m | GSSS | 1988 |
| 32 | Tham Lumphini Suan Hin | Saraburi | 2,245m | TCKG/DMR | 1998/2023 |
| 33 | Tham Pha Daeng | Chiang Mai | 2,190m | APS | 1985 |
| 34 | Tham Khamin | Surat Thani | 2,182m | DMR | 2026 |
| 35 | Tham Nam Dan | Phitsanulok | 2,137m | RFD/CSS/SMCC/OCC | 2002-2004 |
| 36 | Tham Thep Udom Mongkhon | Lampang | 2,132m | SMCC | 2026 |
| 37 | Tham Plup Pla Ta Yom | Surat Thani | 2,110m | Thailand International Caving Expedition | 2020 |
| 38 | Tham Thewada | Krabi | 2,018m | SMCC | 2013 |
| 39 | Tham Than Nam Lot Yai | Chumphon | 1,940m | DMR | 2021 |
| 40 | Tham Gloua | Mae Hong Son | 1,939m | NUEA expeditions | 2025 |
| 41 | Cave NA0122/NA0135 | Nan | 1,929m | SMCC | 2014 |
| 42 | Tham Ki Mi | Chiang Mai | 1,913m | Alpinistyczny Klub Eksploracyjny w Sopocie | 1987 |
| 43 | Tham Than Lot | Tak | 1,877m | RFD/OCC | 1998 |
| 44 | Tham Ya Wua Yai/Tham Phet | Phang Nga | 1,876m | APS/RFD | 1987 |
| 45 | Tham To Wang | Satun | 1,850m | Ko Tao Divers | 2023-24 |
| 46 | Tham Hued/Tham Christmas | Mae Hong Son | 1,840m | APS/M. Foakes | 1988/1998 |
| 47 | Tham Sila Tiab | Surat Thani | 1,825m | Thailand International Caving Expedition | 2020 |
| 48 | Tham Huai Tong Thai | Kanchanaburi | 1,819m | RFD/CSS/CSCA/TVCC | 2004 |
| 49 | Tham Pha Daeng (MH0099) | Mae Hong Son | 1,806m | APS/Australian expeditions | 1986 |
| 50 | Tham Mae Pla Sao | Chiang Mai | 1,762m | Thailand Karst Hydrologic Survey/V. Zeitoun et al. | 1984-2008 |
| 51 | Tham Pakarang | Mae Hong Son | 1,741m | Australian expeditions/SMCC | 1988-90/2019 |
| 52 | Tham Hong | Nakhon Si Thammarat | 1,730m | P. Ashwell | 2012-14 |
| 53 | Tham Tab Tao | Chiang Mai | 1,685m | SMCC | 2003 |
| 54 | Tham Luang Cha | Krabi | 1,683m | D. Rateau & R. Bell | 2024-25 |
| 55 | Tham Lod | Mae Hong Son | 1,666m | Australian expeditions | 1983 |
| 56 | Tham Pang Kham | Mae Hong Son | 1,643m | Unknown surveyor | Unknown date |
| 57 | Tham Huai Chi Laeng | Chaiyaphum | 1,602m | British expedition | 1989 |
| 58 | Tham Pha Ngam | Lampang | 1,578m | SMCC | 2009-2012 |
| 59 | Tham Lek Lek | Krabi | 1,535m | Krabi Family Expedition | 2016-2020 |
| 60 | Tham Long Yaow | Mae Hong Son | 1,528m | SMCC | 2026 |
| 61 | Tham Racha Phuttha | Phang Nga | 1,504m | SMCC | 2010-2012 |
| 62 | Tham Mae Usu | Tak | 1,495m | SMCC | 2003 |
| 63 | Tham Sai Thong | Chiang Rai | 1,458m | MCRO/SMCC | 2019-2022 |
| 64 | Tham Khao Naman Daeng | Krabi | 1,445m | D. Rateau et al. | 2025 |
| 65 | Tham Wiang Fah | Chiang Mai | 1,414m | CMRCA | 2020 |
| 66 | Tham Ruea | Phitsanulok | 1,408m | RFD/OCC | 2003 |
| 67 | Tham Nam Tok | Mae Hong Son | 1,405m | Australian expeditions | 1986 |
| 68 | Tham Duean/Tham Dao | Phitsanulok | 1,382m | RFD/CSS | 1997 |
| 69 | Tham Nam Phra Tat | Kanchanaburi | 1,332m | NZSS | 1992 |
| 70 | Tham Phaya Nakharat | Khon Kaen | 1,331m | DMR | 2023-2024 |
| 71 | Tham Pha Daeng (MH0066) | Mae Hong Son | 1,323m | Australian expeditions | 1988 |
| 72 | Tham Phaya Naak | Phetchabun | 1,285m | SMCC | 2003-2006 |
| 73 | Tham Hub Pha Khao | Chiang Mai | 1,254m | SMCC/CMRCA | 2020 |
| 74 | Tham Tapan | Phang Nga | 1,250m | Australian expeditions | 1986 |
| 75 | Tham Pha Kaeo | Phitsanulok | 1,217m | RFD/OCC | 2004 |
| = | Tham Phung Chang | Phang Nga | 1,217m | DMR | 2022 |
| 76 | Tham Nam Hu | Mae Hong Son | 1,201m | Pang Ma Pha Cave Project | 1999 |
| 78 | Tham Pha Phuek | Mae Hong Son | 1,152m | NUEA expeditions | 2024-2025 |
| 79 | Tham Mor | Tak | 1,135m | RFD | 1999 |
| 80 | Tham Sao Hin | Kanchanaburi | 1,130m | Australian expeditions | 1990 |
| 81 | Tham Seri Thai | Sakon Nakhon | 1,124m | Clubul de Speologie "Z" | 2023-2025 |
| 82 | Tham Pla | Surat Thani | 1,103m | BEC | 1998 |
| 83 | Tham Chao Ram | Sukhothai | 1,091m | RFD/CSS | 1996-1997 |
| 84 | Tham Krata | Lamphun | 1,057m | BEC | 2001 |
| = | Tham Yai Nakarat/Tham Kai | Phisanulok | 1,057m | SMCC | 2019 |
| 86 | Tham Khun Huai Tum Lek | Phitsanulok | 1,035m | SMCC | 2004 |
| 87 | Tham Nong Lai | Surat Thani | 1,032m | Thailand International Caving Expedition | 2020 |
| 88 | Tham Patihan | Ubon Ratchathani | 1,029m | Clubul de Speologie "Z" | 2024-2025 |
| 89 | Tham Pha Thai | Lampang | 1,025m | CMRCA | 2020 |
| 90 | Tham Yai | Kanchanaburi | 1,021m | GSSS | 1988 |
| 91 | Tham Mae Usa | Tak | 1,019m | SMCC | 2003 |
