The busiest time of the week for travel from Lille to Saint-Quentin by bus is at 10:00 a.m. on Sunday. When planning to travel around this time, tickets should be booked well in advance as they may sell out. Around 11:00 a.m. on Wednesday is when the fewest number of bus tickets are sold. If you’re looking for a little extra space, the bus departing at this time is the least likely to be crowded.