When you’ve been building in the cloud long enough, certain patterns become second nature—like placing a NAT Gateway inside a public subnet in each Availability Zone so your private workloads can reach the internet. It’s predictable, reliable, and… honestly, a little outdated.

This year, AWS quietly changed the game with a feature that fundamentally simplifies traditional NAT architectures:
the Amazon VPC Regional NAT Gateway (RNAT).

What began as a small curiosity turned into a full-scale experiment. I built test environments, pushed traffic through multiple AZs, deleted subnets I shouldn’t delete, forced expansions, and watched the behavior unfold.

This blog captures everything I learned — the “why,” the “how,” and the “wow” moments that prove RNAT isn’t just new… it’s transformational.

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Why Traditional NAT Needed an Upgrade

Traditional NAT Gateways (zonal NATs) have served well for years, but they come with well-known limitations:

❌ Cross-AZ Charges Add Up

A private instance in AZ-B using a NAT Gateway in AZ-A incurs cross-AZ data charges. That adds unnecessary expense.

❌ One NAT per AZ = Higher Cost & Complexity

A three-AZ VPC means:

• 3 NAT Gateways

• 3 Elastic IPs

• 3 public subnets

• 3 sets of routing rules

❌ NAT Gateway Failure = AZ-Level Outage

If the AZ hosting your NAT gateway has issues, private subnets in that AZ lose internet access unless you deployed redundant NATs.

❌ Public Subnet Required per AZ

You must create public subnets even when you don’t want any public infrastructure.

These pain points set the stage for something better.

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Enter the Regional NAT Gateway — A Smarter Way Forward

The Amazon VPC Regional NAT Gateway (RNAT) is fundamentally different.

RNAT is a VPC-wide, region-scoped NAT service that automatically supports all Availability Zones—without needing multiple NAT gateways or public subnets.

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Why RNAT Is a Game Changer

1. One NAT for the Whole Region

Instead of one NAT per AZ, RNAT gives you:

1 Regional NAT Gateway → All AZs Covered

No need to repeat NAT infrastructure for each AZ.

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2. No Cross-AZ NAT Charges

Traffic no longer jumps AZs for NAT processing.

Everything is handled regionally → zero cross-AZ NAT charges.

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3. Automatic Expansion Into New AZs

If traffic appears in a new Availability Zone, RNAT expands automatically.

No Terraform updates.
No additional NAT gateways.
No manual routing changes.

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4. No Public Subnet Required

RNAT is not deployed inside a subnet.

You can delete your public subnet, and RNAT continues working.

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5. Automatic Port & EIP Scaling

Under heavy traffic, RNAT automatically increases:

• Connection capacity

• Elastic IP count

• Per-AZ presence

No admin intervention needed.

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6. High Availability Built-In

RNAT inherently spans multiple AZs.

An AZ outage doesn’t take NAT down.

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How I Tested RNAT (And What I Observed)

Here’s what I actually tried while experimenting:

✔ EC2s in multiple AZs all used the same RNAT IP

✔ deleting the public subnet did NOT break NAT

✔ RNAT expanded into unused AZs within ~20–60 mins

✔ Heavy traffic caused RNAT to add more EIPs dynamically

✔ No cross-AZ charges appeared in billing

The experience was shockingly smooth.

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Step-by-Step: Creating a Regional NAT Gateway

This section includes visual guides so you can follow along easily.

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🔹 Step 1 — Open NAT Gateway Console

Go to:

VPC Console → NAT Gateways → Create NAT Gateway

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🔹 Step 2 — Select Availability Mode: REGIONAL

This is the most important option.

Choose:

This tells AWS you want a single NAT Gateway that spans the entire region.

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🔹 Step 3 — Choose Your VPC & Elastic IP

You do not select a subnet (because RNAT is not tied to one).

Just pick:

• VPC name

• Elastic IP (automatic or custom)

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🔹 Step 4 — Create the NAT Gateway

Click Create NAT Gateway.

Within seconds, RNAT is ready.

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🔹 Step 5 — Update Private Subnet Route Tables

Route:

0.0.0.0/0 → Regional NAT Gateway

Done. Your workloads now use RNAT for outbound traffic.

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How RNAT Solves NAT Cost and Complexity Issues

Let’s compare the two architectures.

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🆚 Traditional Zonal NAT vs Regional NAT

Traditional NAT (Before)

AZ-a → NAT A → IGW  
AZ-b → NAT B → IGW  
AZ-c → NAT C → IGW

Problems:

• 3 NAT gateways minimum

• 3 public subnets

• Cross-AZ charges

• AZ-specific routing

• High cost

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Regional NAT (Now)

ALL private subnets → 1 RNAT → IGW

Benefits:

• Only 1 NAT required

• No cross-AZ charges

• No public subnets required

• Auto-expands to new AZs

• Greatly simplified routing

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Where RNAT Fits Best

RNAT is ideal for:

• Modern multi-AZ microservices

• Private-only VPC designs

• Highly secure architectures

• Environments with heavy S3/SSM usage

• Teams wanting fewer moving parts

• Cost-optimized cloud networks

It simplifies almost everything.

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Final Thoughts: RNAT Is the Future of NAT in AWS

After researching and testing RNAT extensively, here’s my honest conclusion:

Regional NAT Gateway is the most meaningful improvement to VPC egress in years.
It simplifies design, reduces cost, and adds resilience—all at once.

If you're planning a new VPC or modernizing an existing one, RNAT should be the default choice.