| Rank | AS number | Organization | IPv4 addresses |
|---|---|---|---|
| 1 | AS5610 | O2-CZECH-REPUBLIC O2 Czech Republic, a.s. | 1,540,608 |
| 2 | AS16019 | VODAFONE-CZ-AS Vodafone Czech Republic a.s. | 1,210,368 |
| 3 | AS13036 | TMOBILE-CZ T-Mobile Czech Republic a.s. | 992,255 |
| 4 | AS2852 | CESNET2 CESNET z.s.p.o. | 849,920 |
| 5 | AS29208 | QUANTCOM-AS Quantcom, a.s. | 265,984 |
| 6 | AS30764 | PODA-AS PODA a.s. | 218,112 |
| 7 | AS42908 | CZ-NORDICTELECOMREGIONAL O2 Czech Republic, a.s. | 183,296 |
| 8 | AS2571 | DHL Information Services (Europe) s.r.o | 152,832 |
| 9 | AS28725 | CETIN-AS CETIN a.s. | 134,400 |
| 10 | AS16246 | AS16246 O2 Czech Republic, a.s. | 133,120 |
| 11 | AS25512 | CDT-AS CD-Telematika a.s. | 117,760 |
| 12 | AS15425 | COMA PODA a.s. | 110,592 |
| 13 | AS44546 | ALFATELECOM-AS ALFA TELECOM s.r.o. | 110,592 |
| 14 | AS25248 | BlueTone-AS RADIOKOMUNIKACE a.s. | 106,752 |
This product includes GeoLite2 data created by MaxMind, available from https://www.maxmind.com.