| NAT Instance | NAT Gateway |
|---|
| NAT instance is managed by you | NAT gateway is managed by AWS |
| NAT instance can be scaled up manually | NAT Gateway provides elastic scalability of up to 45 GB |
| NAT instance does not provide High Availability | NAT Gateway provides High Availability and can be deployed across multiple AZ |
| Security group needs to be assigned to NAT Instance | No security group is required for NAT Gateway |
| NAT instance can use a bastion host | NAT Gateway cannot be accessed through SSH |
| Can implement port forwarding in NAT instance | Does not support port forwarding in NAT Gateway |