How the two terms play out
Prepaid: the shipper (or the party arranging export) settles the freight at origin, so the cargo arrives with the main carriage already paid. This is normal when the seller controls the freight — for example selling on CFR, CIF, CPT, CIP, or DAP/DDP terms — and it gives the seller control over carrier choice and routing. Prepaid freight is typically invoiced at departure, or at booking by agreement.
Collect: the consignee pays the freight at destination before the cargo is released. This fits terms where the buyer controls the main carriage — FOB, FCA, EXW — often via the buyer's own forwarder. Collect freight is invoiced at destination delivery, and release can be gated on payment, which is part of the leverage.
The Incoterm link and the traps
Prepaid/collect is a payment mechanic; the Incoterm is the cost-and-risk allocation. They must be consistent: a shipment sold CIF (seller pays main freight) should be freight prepaid, while one sold FOB (buyer pays) should be freight collect. TMS and quoting systems should flag mismatches, because an inconsistent B/L causes double-billing or a party being charged freight they never agreed to bear.
Two practical risks. On collect shipments, the carrier or forwarder carries destination credit exposure — if the consignee won't pay, the cargo (and the freight owed) is stuck, which is why collect on unknown consignees is a credit decision. On prepaid, watch that 'freight prepaid' covers only what was actually prepaid — destination local charges (THC, delivery, D&D) are frequently separate and land on the consignee regardless, the source of many 'but I paid prepaid' arguments at destination.

