A combination of letters and numbers used to identify a fare type which may also indicate the rules of the fare
| Fare Basis Code Example | Definition |
| A or AP | Advance Purchase |
| D | Fare valid on a specified day(s) |
| E | Excursion |
| FLT | Flight |
| H | High season/high traffic |
| HOL | Holiday |
| L | Low season |
| N or NR | Non-refundable |
| P | Penalty for change/cancel |
| R | Round trip |
| SALE | “SALE” |
| SAT | Saturday |
| W | Weekend |
| X | Except |
| Z | Fare valid on a specified day(s) |
| 1234567 | Day of the week; 1= Mon, 2= Tue, etc. |
| 1,3,7,14,21,30 | Number of days in advance of travel the ticket must be purchased |
