diff --git a/README.md b/README.md
index 79c48ffa..b6e67983 100644
--- a/README.md
+++ b/README.md
@@ -237,7 +237,7 @@ Now you're ready to go!
 | `mode` | Always required. | Specify here which mode you want to use: <br> - `start` - to start a new runner; <br> - `stop` - to stop the previously created runner. |
 | `github-token` | Always required. | GitHub Personal Access Token with the `repo` scope assigned. |
 | `ec2-image-id` | Required if you use the `start` mode and don't provide `availability-zones-config`. | EC2 Image Id (AMI). The new runner will be launched from this image. Compatible with Amazon Linux 2, Amazon Linux 2023, and Ubuntu images. |
-| `ec2-instance-type` | Required if you use the `start` mode. | EC2 Instance Type. |
+| `ec2-instance-type` | Required if you use the `start` mode. | EC2 Instance Type. Accepts a single type (e.g. `t3.micro`) or a JSON array of types (e.g. `'["t3.micro", "t3.small", "m5.large"]'`). When multiple types are specified, the action tries each in order until one succeeds. Useful for spot instances where capacity may vary by type. |
 | `subnet-id` | Required if you use the `start` mode and don't provide `availability-zones-config`. | VPC Subnet Id. The subnet should belong to the same VPC as the specified security group. |
 | `security-group-id` | Required if you use the `start` mode and don't provide `availability-zones-config`. | EC2 Security Group Id. The security group should belong to the same VPC as the specified subnet. Only outbound traffic for port 443 is required. No inbound traffic is required. |
 | `label` | Required if you use the `stop` mode. | Name of the unique label assigned to the runner. The label is provided by the output of the action in the `start` mode. |
@@ -400,6 +400,26 @@ Each configuration object requires `imageId`, `subnetId`, and `securityGroupId`.
             ]
 ```
 
+### Advanced: Multiple instance types
+
+When using spot instances, a specific instance type may not have available capacity. By specifying multiple instance types as a JSON array, the action will try each type in order until one succeeds. This is especially powerful when combined with multi-AZ failover — the action tries all instance types within each AZ before moving to the next AZ.
+
+```yml
+      - name: Start EC2 runner
+        id: start-ec2-runner
+        uses: machulav/ec2-github-runner@v2
+        with:
+          mode: start
+          github-token: ${{ secrets.GH_PERSONAL_ACCESS_TOKEN }}
+          ec2-image-id: ami-123
+          ec2-instance-type: '["c5.xlarge", "c5a.xlarge", "c5d.xlarge", "m5.xlarge"]'
+          subnet-id: subnet-123
+          security-group-id: sg-123
+          market-type: spot
+```
+
+> **Tip:** Choose instance types with similar vCPU/memory specs so your workload runs consistently regardless of which type is selected.
+
 ### Advanced: Debug mode
 
 When a runner fails to register, it can be difficult to diagnose the issue because user-data scripts execute on the remote EC2 instance. The `runner-debug` input enables verbose logging to help with troubleshooting.
diff --git a/action.yml b/action.yml
index 3f4f12c2..d6596da2 100644
--- a/action.yml
+++ b/action.yml
@@ -32,7 +32,10 @@ inputs:
     required: false
   ec2-instance-type:
     description: >-
-      EC2 Instance Type.
+      EC2 Instance Type. Accepts a single instance type (e.g. 't3.micro') or a JSON array
+      of instance types (e.g. '["t3.micro", "t3.small", "m5.large"]').
+      When multiple types are provided, the action tries each type in order until one succeeds.
+      This is especially useful with spot instances where a specific instance type may not have capacity.
       This input is required if you use the 'start' mode.
     required: false
   subnet-id:
diff --git a/dist/index.js b/dist/index.js
index b0e1851a..ae6c61d0 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -145221,7 +145221,7 @@ function buildMarketOptions() {
   };
 }
 
-async function createEc2InstanceWithParams(imageId, subnetId, securityGroupId, label, githubRegistrationToken, region, encodedJitConfig) {
+async function createEc2InstanceWithParams(imageId, subnetId, securityGroupId, label, githubRegistrationToken, region, encodedJitConfig, instanceType) {
   // Region is always specified now, so we can directly use it
   const ec2ClientOptions = { region };
   const ec2 = new EC2Client(ec2ClientOptions);
@@ -145230,7 +145230,7 @@ async function createEc2InstanceWithParams(imageId, subnetId, securityGroupId, l
 
   const params = {
     ImageId: imageId,
-    InstanceType: config.input.ec2InstanceType,
+    InstanceType: instanceType,
     MaxCount: 1,
     MinCount: 1,
     SecurityGroupIds: [securityGroupId],
@@ -145264,7 +145264,8 @@ async function createEc2InstanceWithParams(imageId, subnetId, securityGroupId, l
 }
 
 async function startEc2Instance(label, githubRegistrationToken, encodedJitConfig) {
-  core.info(`Attempting to start EC2 instance using ${config.availabilityZones.length} availability zone configuration(s)`);
+  const instanceTypes = config.input.ec2InstanceTypes;
+  core.info(`Attempting to start EC2 instance using ${config.availabilityZones.length} availability zone configuration(s) and ${instanceTypes.length} instance type(s): ${instanceTypes.join(', ')}`);
 
   const errors = [];
 
@@ -145276,32 +145277,35 @@ async function startEc2Instance(label, githubRegistrationToken, encodedJitConfig
     core.info(`Trying availability zone configuration ${i + 1}/${config.availabilityZones.length}`);
     core.info(`Using imageId: ${azConfig.imageId}, subnetId: ${azConfig.subnetId}, securityGroupId: ${azConfig.securityGroupId}, region: ${region}`);
 
-    try {
-      const ec2InstanceId = await createEc2InstanceWithParams(
-        azConfig.imageId,
-        azConfig.subnetId,
-        azConfig.securityGroupId,
-        label,
-        githubRegistrationToken,
-        region,
-        encodedJitConfig
-      );
-
-      core.info(`Successfully started AWS EC2 instance ${ec2InstanceId} using availability zone configuration ${i + 1} in region ${region}`);
-      return { ec2InstanceId, region };
-    } catch (error) {
-      const errorMessage = `Failed to start EC2 instance with configuration ${i + 1} in region ${region}: ${error.message}`;
-      core.warning(errorMessage);
-      errors.push(errorMessage);
+    // Try each instance type within this AZ configuration
+    for (const instanceType of instanceTypes) {
+      core.info(`Trying instance type: ${instanceType}`);
+      try {
+        const ec2InstanceId = await createEc2InstanceWithParams(
+          azConfig.imageId,
+          azConfig.subnetId,
+          azConfig.securityGroupId,
+          label,
+          githubRegistrationToken,
+          region,
+          encodedJitConfig,
+          instanceType
+        );
 
-      // Continue to the next availability zone configuration
-      continue;
+        core.info(`Successfully started AWS EC2 instance ${ec2InstanceId} (type: ${instanceType}) using availability zone configuration ${i + 1} in region ${region}`);
+        return { ec2InstanceId, region };
+      } catch (error) {
+        const errorMessage = `Failed to start EC2 instance (type: ${instanceType}) with AZ configuration ${i + 1} in region ${region}: ${error.message}`;
+        core.warning(errorMessage);
+        errors.push(errorMessage);
+        continue;
+      }
     }
   }
 
-  // If we've tried all configurations and none worked, throw an error
-  core.error('All availability zone configurations failed');
-  throw new Error(`Failed to start EC2 instance in any availability zone. Errors: ${errors.join('; ')}`);
+  // If we've tried all configurations and instance types and none worked, throw an error
+  core.error('All availability zone configurations and instance types failed');
+  throw new Error(`Failed to start EC2 instance with any configuration. Errors: ${errors.join('; ')}`);
 }
 
 async function terminateEc2Instance() {
@@ -145409,6 +145413,7 @@ class Config {
       ec2ImageId: core.getInput('ec2-image-id'),
       ec2InstanceId: core.getInput('ec2-instance-id'),
       ec2InstanceType: core.getInput('ec2-instance-type'),
+      ec2InstanceTypes: [],
       githubToken: core.getInput('github-token'),
       iamRoleName: core.getInput('iam-role-name'),
       label: core.getInput('label'),
@@ -145506,6 +145511,28 @@ class Config {
         throw new Error(`The 'ec2-instance-type' input is required for the 'start' mode.`);
       }
 
+      // Parse ec2-instance-type: supports a single string or a JSON array of strings
+      const rawType = this.input.ec2InstanceType.trim();
+      if (rawType.startsWith('[')) {
+        try {
+          this.input.ec2InstanceTypes = JSON.parse(rawType);
+          if (!Array.isArray(this.input.ec2InstanceTypes) || this.input.ec2InstanceTypes.length === 0) {
+            throw new Error('must be a non-empty JSON array of strings');
+          }
+          for (const t of this.input.ec2InstanceTypes) {
+            if (typeof t !== 'string' || t.trim().length === 0) {
+              throw new Error('each element must be a non-empty string');
+            }
+          }
+        } catch (error) {
+          throw new Error(`Invalid 'ec2-instance-type' input: ${error.message}`);
+        }
+      } else {
+        this.input.ec2InstanceTypes = [rawType];
+      }
+      // Keep ec2InstanceType pointing to the first type for backward compatibility
+      this.input.ec2InstanceType = this.input.ec2InstanceTypes[0];
+
       // If no availability zones config provided, check for individual parameters
       if (this.availabilityZones.length === 0) {
         if (!this.input.ec2ImageId || !this.input.subnetId || !this.input.securityGroupId) {
diff --git a/src/__tests__/jit.test.js b/src/__tests__/jit.test.js
index c114d2fe..c651d9bc 100644
--- a/src/__tests__/jit.test.js
+++ b/src/__tests__/jit.test.js
@@ -291,6 +291,47 @@ describe('aws.js - runner-debug', () => {
   });
 });
 
+describe('Config - ec2-instance-type parsing', () => {
+  beforeEach(() => {
+    process.env.AWS_REGION = 'us-east-1';
+  });
+
+  test('parses single instance type string into array', () => {
+    setupInputs({ 'ec2-instance-type': 't3.micro' });
+    const config = createConfig();
+    expect(config.input.ec2InstanceTypes).toEqual(['t3.micro']);
+    expect(config.input.ec2InstanceType).toBe('t3.micro');
+  });
+
+  test('parses JSON array of instance types', () => {
+    setupInputs({ 'ec2-instance-type': '["t3.micro", "t3.small", "m5.large"]' });
+    const config = createConfig();
+    expect(config.input.ec2InstanceTypes).toEqual(['t3.micro', 't3.small', 'm5.large']);
+    expect(config.input.ec2InstanceType).toBe('t3.micro');
+  });
+
+  test('throws on empty JSON array', () => {
+    setupInputs({ 'ec2-instance-type': '[]' });
+    expect(() => createConfig()).toThrow("Invalid 'ec2-instance-type' input");
+  });
+
+  test('throws on invalid JSON array content', () => {
+    setupInputs({ 'ec2-instance-type': '[123, 456]' });
+    expect(() => createConfig()).toThrow("Invalid 'ec2-instance-type' input");
+  });
+
+  test('throws on malformed JSON', () => {
+    setupInputs({ 'ec2-instance-type': '[not json' });
+    expect(() => createConfig()).toThrow("Invalid 'ec2-instance-type' input");
+  });
+
+  test('handles whitespace around single type', () => {
+    setupInputs({ 'ec2-instance-type': '  t3.micro  ' });
+    const config = createConfig();
+    expect(config.input.ec2InstanceTypes).toEqual(['t3.micro']);
+  });
+});
+
 describe('Config - runner-debug input', () => {
   beforeEach(() => {
     process.env.AWS_REGION = 'us-east-1';
diff --git a/src/aws.js b/src/aws.js
index effbfc0b..e24382e3 100644
--- a/src/aws.js
+++ b/src/aws.js
@@ -213,7 +213,7 @@ function buildMarketOptions() {
   };
 }
 
-async function createEc2InstanceWithParams(imageId, subnetId, securityGroupId, label, githubRegistrationToken, region, encodedJitConfig) {
+async function createEc2InstanceWithParams(imageId, subnetId, securityGroupId, label, githubRegistrationToken, region, encodedJitConfig, instanceType) {
   // Region is always specified now, so we can directly use it
   const ec2ClientOptions = { region };
   const ec2 = new EC2Client(ec2ClientOptions);
@@ -222,7 +222,7 @@ async function createEc2InstanceWithParams(imageId, subnetId, securityGroupId, l
 
   const params = {
     ImageId: imageId,
-    InstanceType: config.input.ec2InstanceType,
+    InstanceType: instanceType,
     MaxCount: 1,
     MinCount: 1,
     SecurityGroupIds: [securityGroupId],
@@ -256,7 +256,8 @@ async function createEc2InstanceWithParams(imageId, subnetId, securityGroupId, l
 }
 
 async function startEc2Instance(label, githubRegistrationToken, encodedJitConfig) {
-  core.info(`Attempting to start EC2 instance using ${config.availabilityZones.length} availability zone configuration(s)`);
+  const instanceTypes = config.input.ec2InstanceTypes;
+  core.info(`Attempting to start EC2 instance using ${config.availabilityZones.length} availability zone configuration(s) and ${instanceTypes.length} instance type(s): ${instanceTypes.join(', ')}`);
 
   const errors = [];
 
@@ -268,32 +269,35 @@ async function startEc2Instance(label, githubRegistrationToken, encodedJitConfig
     core.info(`Trying availability zone configuration ${i + 1}/${config.availabilityZones.length}`);
     core.info(`Using imageId: ${azConfig.imageId}, subnetId: ${azConfig.subnetId}, securityGroupId: ${azConfig.securityGroupId}, region: ${region}`);
 
-    try {
-      const ec2InstanceId = await createEc2InstanceWithParams(
-        azConfig.imageId,
-        azConfig.subnetId,
-        azConfig.securityGroupId,
-        label,
-        githubRegistrationToken,
-        region,
-        encodedJitConfig
-      );
-
-      core.info(`Successfully started AWS EC2 instance ${ec2InstanceId} using availability zone configuration ${i + 1} in region ${region}`);
-      return { ec2InstanceId, region };
-    } catch (error) {
-      const errorMessage = `Failed to start EC2 instance with configuration ${i + 1} in region ${region}: ${error.message}`;
-      core.warning(errorMessage);
-      errors.push(errorMessage);
-
-      // Continue to the next availability zone configuration
-      continue;
+    // Try each instance type within this AZ configuration
+    for (const instanceType of instanceTypes) {
+      core.info(`Trying instance type: ${instanceType}`);
+      try {
+        const ec2InstanceId = await createEc2InstanceWithParams(
+          azConfig.imageId,
+          azConfig.subnetId,
+          azConfig.securityGroupId,
+          label,
+          githubRegistrationToken,
+          region,
+          encodedJitConfig,
+          instanceType
+        );
+
+        core.info(`Successfully started AWS EC2 instance ${ec2InstanceId} (type: ${instanceType}) using availability zone configuration ${i + 1} in region ${region}`);
+        return { ec2InstanceId, region };
+      } catch (error) {
+        const errorMessage = `Failed to start EC2 instance (type: ${instanceType}) with AZ configuration ${i + 1} in region ${region}: ${error.message}`;
+        core.warning(errorMessage);
+        errors.push(errorMessage);
+        continue;
+      }
     }
   }
 
-  // If we've tried all configurations and none worked, throw an error
-  core.error('All availability zone configurations failed');
-  throw new Error(`Failed to start EC2 instance in any availability zone. Errors: ${errors.join('; ')}`);
+  // If we've tried all configurations and instance types and none worked, throw an error
+  core.error('All availability zone configurations and instance types failed');
+  throw new Error(`Failed to start EC2 instance with any configuration. Errors: ${errors.join('; ')}`);
 }
 
 async function terminateEc2Instance() {
diff --git a/src/config.js b/src/config.js
index 1892a123..21cb18bf 100644
--- a/src/config.js
+++ b/src/config.js
@@ -7,6 +7,7 @@ class Config {
       ec2ImageId: core.getInput('ec2-image-id'),
       ec2InstanceId: core.getInput('ec2-instance-id'),
       ec2InstanceType: core.getInput('ec2-instance-type'),
+      ec2InstanceTypes: [],
       githubToken: core.getInput('github-token'),
       iamRoleName: core.getInput('iam-role-name'),
       label: core.getInput('label'),
@@ -104,6 +105,28 @@ class Config {
         throw new Error(`The 'ec2-instance-type' input is required for the 'start' mode.`);
       }
 
+      // Parse ec2-instance-type: supports a single string or a JSON array of strings
+      const rawType = this.input.ec2InstanceType.trim();
+      if (rawType.startsWith('[')) {
+        try {
+          this.input.ec2InstanceTypes = JSON.parse(rawType);
+          if (!Array.isArray(this.input.ec2InstanceTypes) || this.input.ec2InstanceTypes.length === 0) {
+            throw new Error('must be a non-empty JSON array of strings');
+          }
+          for (const t of this.input.ec2InstanceTypes) {
+            if (typeof t !== 'string' || t.trim().length === 0) {
+              throw new Error('each element must be a non-empty string');
+            }
+          }
+        } catch (error) {
+          throw new Error(`Invalid 'ec2-instance-type' input: ${error.message}`);
+        }
+      } else {
+        this.input.ec2InstanceTypes = [rawType];
+      }
+      // Keep ec2InstanceType pointing to the first type for backward compatibility
+      this.input.ec2InstanceType = this.input.ec2InstanceTypes[0];
+
       // If no availability zones config provided, check for individual parameters
       if (this.availabilityZones.length === 0) {
         if (!this.input.ec2ImageId || !this.input.subnetId || !this.input.securityGroupId) {