NAT Gateways are convenient for enabling outbound access from private subnets, but in data-intensive environments, they can quietly become a major cost driver. When large volumes of traffic flow through the gateway—particularly during batch processing, frequent software updates, or hybrid cloud integrations—the per-GB charges accumulate rapidly. In some cases, replacing a managed NAT Gateway with a self-managed NAT instance can substantially reduce costs, provided that the organization is prepared to operate and maintain the alternative solution.

NAT Gateways are frequently left running after environments are re-architected, workloads are shut down, or connectivity patterns change. In many cases, they continue to incur hourly charges despite no active traffic flowing through them. Because hourly fees are not tied to whether the gateway is needed—just whether it exists—these resources can quietly drive recurring costs without delivering ongoing value. Identifying and removing unused gateways is a simple way to reduce waste.