Which of the following best describes Southwest's check-in timeline?

The check-in timeline for Southwest Airlines is best described as occurring 24 hours prior to the flight departure. This policy allows passengers to check in and obtain their boarding passes online, which is essential for facilitating a smooth travel experience. Checking in early can also be beneficial as it often affects the boarding group assignments, giving passengers a better chance to select preferred seating. The online check-in process typically opens at this 24-hour mark and remains open until a few minutes before the flight’s departure.

While the other options suggest alternative check-in times, they do not align with Southwest’s clear policy of allowing passengers to check in exactly 24 hours before their scheduled departure, making the provided answer the most accurate choice.