diff --git a/Cargo.lock b/Cargo.lock
index ef7c147..e9af7be 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2153,7 +2153,9 @@ dependencies = [
  "aws-credential-types",
  "aws-sdk-s3",
  "aws-sigv4",
+ "aws-smithy-runtime-api",
  "aws-smithy-types",
+ "bytes",
  "futures",
  "hex",
  "http 1.4.0",
diff --git a/Cargo.toml b/Cargo.toml
index 4951b9b..7b77ece 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,6 +27,7 @@ aws-sdk-s3 = "1.119"
 aws-config = { version = "1.8", features = ["behavior-version-latest"] }
 aws-credential-types = "1.2"
 aws-smithy-types = "1.3"
+aws-smithy-runtime-api = "1.9"
 
 # CLI
 clap = { version = "4.5", features = ["derive", "env"] }
@@ -54,6 +55,7 @@ console = "0.16"
 dirs = "6.0"
 jiff = { version = "0.2", features = ["serde"] }
 humansize = "2.1"
+bytes = "1.11"
 url = "2.5"
 futures = "0.3"
 async-trait = "0.1"
diff --git a/crates/s3/Cargo.toml b/crates/s3/Cargo.toml
index 4adc890..0b56f40 100644
--- a/crates/s3/Cargo.toml
+++ b/crates/s3/Cargo.toml
@@ -20,6 +20,7 @@ aws-sdk-s3.workspace = true
 aws-config.workspace = true
 aws-credential-types.workspace = true
 aws-smithy-types.workspace = true
+aws-smithy-runtime-api.workspace = true
 
 # Async
 tokio.workspace = true
@@ -35,6 +36,7 @@ tracing.workspace = true
 
 # Utilities
 jiff.workspace = true
+bytes.workspace = true
 url.workspace = true
 
 # HTTP client for Admin API
diff --git a/crates/s3/src/client.rs b/crates/s3/src/client.rs
index 707a895..22944d3 100644
--- a/crates/s3/src/client.rs
+++ b/crates/s3/src/client.rs
@@ -3,13 +3,153 @@
 //! Wraps aws-sdk-s3 and implements the ObjectStore trait from rc-core.
 
 use async_trait::async_trait;
-
+use aws_smithy_runtime_api::client::http::{
+    HttpClient, HttpConnector, HttpConnectorFuture, HttpConnectorSettings, SharedHttpConnector,
+};
+use aws_smithy_runtime_api::client::orchestrator::HttpRequest;
+use aws_smithy_runtime_api::client::result::ConnectorError;
+use aws_smithy_runtime_api::client::runtime_components::RuntimeComponents;
+use aws_smithy_runtime_api::http::{Response, StatusCode};
+use aws_smithy_types::body::SdkBody;
+use bytes::Bytes;
 use jiff::Timestamp;
 use rc_core::{
     Alias, Capabilities, Error, ListOptions, ListResult, ObjectInfo, ObjectStore, ObjectVersion,
     RemotePath, Result,
 };
 
+/// Custom HTTP connector using reqwest, supporting insecure TLS (skip cert verification)
+/// and custom CA bundles. Used when `alias.insecure = true` or `alias.ca_bundle.is_some()`.
+#[derive(Debug, Clone)]
+struct ReqwestConnector {
+    client: reqwest::Client,
+}
+
+impl ReqwestConnector {
+    async fn new(insecure: bool, ca_bundle: Option<&str>) -> Result<Self> {
+        // NOTE: When `insecure = true`, `danger_accept_invalid_certs` disables all TLS
+        // certificate verification. Any CA bundle provided will still be added to the
+        // trust store but is rendered ineffective for this connection.
+        let mut builder = reqwest::Client::builder().danger_accept_invalid_certs(insecure);
+
+        if let Some(bundle_path) = ca_bundle {
+            // Use tokio::fs::read to avoid blocking the async runtime thread.
+            let pem = tokio::fs::read(bundle_path).await.map_err(|e| {
+                Error::Network(format!("Failed to read CA bundle '{bundle_path}': {e}"))
+            })?;
+            let cert = reqwest::Certificate::from_pem(&pem)
+                .map_err(|e| Error::Network(format!("Invalid CA bundle '{bundle_path}': {e}")))?;
+            builder = builder.add_root_certificate(cert);
+        }
+
+        let client = builder
+            .build()
+            .map_err(|e| Error::Network(format!("Failed to build HTTP client: {e}")))?;
+        Ok(Self { client })
+    }
+}
+
+impl HttpConnector for ReqwestConnector {
+    fn call(&self, request: HttpRequest) -> HttpConnectorFuture {
+        let client = self.client.clone();
+        HttpConnectorFuture::new(async move {
+            // Extract request parts before consuming the request
+            let uri = request.uri().to_string();
+            let method_str = request.method().to_string();
+            let headers = request.headers().clone();
+
+            // Try to get the body as buffered in-memory bytes.
+            // For streaming bodies (e.g., large file uploads), bytes() returns None and we
+            // return a clear error rather than silently sending an empty body, which would
+            // cause signature mismatches or server-side failures.
+            let body_bytes = match request.body().bytes() {
+                Some(b) => Bytes::copy_from_slice(b),
+                None => {
+                    return Err(ConnectorError::user(
+                        "Streaming request bodies are not supported in insecure/ca_bundle TLS mode; \
+                         use in-memory data for uploads with this connector"
+                            .into(),
+                    ));
+                }
+            };
+
+            // Build reqwest method
+            let method = reqwest::Method::from_bytes(method_str.as_bytes())
+                .map_err(|e| ConnectorError::user(Box::new(e)))?;
+
+            // Build reqwest URL
+            let url = reqwest::Url::parse(&uri).map_err(|e| ConnectorError::user(Box::new(e)))?;
+
+            // Build reqwest request
+            let mut req = reqwest::Request::new(method, url);
+
+            // Copy headers; S3 headers are all ASCII so failures here are unexpected
+            for (name, value) in headers.iter() {
+                match (
+                    reqwest::header::HeaderName::from_bytes(name.as_bytes()),
+                    reqwest::header::HeaderValue::from_bytes(value.as_bytes()),
+                ) {
+                    (Ok(header_name), Ok(header_value)) => {
+                        req.headers_mut().append(header_name, header_value);
+                    }
+                    _ => {
+                        tracing::warn!("Skipping non-convertible request header: {}", name);
+                    }
+                }
+            }
+
+            // Set body
+            *req.body_mut() = Some(reqwest::Body::from(body_bytes));
+
+            // Execute
+            let resp = client
+                .execute(req)
+                .await
+                .map_err(|e| ConnectorError::io(Box::new(e)))?;
+
+            // Convert response
+            let status = StatusCode::try_from(resp.status().as_u16())
+                .map_err(|e| ConnectorError::other(Box::new(e), None))?;
+            let resp_headers = resp.headers().clone();
+            let body = resp
+                .bytes()
+                .await
+                .map_err(|e| ConnectorError::io(Box::new(e)))?;
+
+            let mut sdk_response = Response::new(status, SdkBody::from(body));
+            for (name, value) in &resp_headers {
+                match value.to_str() {
+                    Ok(value_str) => {
+                        sdk_response
+                            .headers_mut()
+                            .append(name.as_str().to_owned(), value_str.to_owned());
+                    }
+                    Err(_) => {
+                        tracing::warn!("Skipping non-UTF8 response header: {}", name.as_str());
+                    }
+                }
+            }
+
+            Ok(sdk_response)
+        })
+    }
+}
+
+impl HttpClient for ReqwestConnector {
+    fn http_connector(
+        &self,
+        _settings: &HttpConnectorSettings,
+        _components: &RuntimeComponents,
+    ) -> SharedHttpConnector {
+        // NOTE: `ReqwestConnector` is preconfigured (e.g., insecure/CA-bundle options) when it
+        // is constructed, and does not currently apply `HttpConnectorSettings`. This means
+        // behavior in this mode may differ from the default connector w.r.t. SDK HTTP settings.
+        // If alignment is required, map relevant fields from `HttpConnectorSettings` onto the
+        // internal `reqwest::Client` when constructing the connector.
+        SharedHttpConnector::new(self.clone())
+    }
+}
+
 /// S3 client wrapper
 pub struct S3Client {
     inner: aws_sdk_s3::Client,
@@ -34,13 +174,21 @@ impl S3Client {
             "rc-static-credentials",
         );
 
-        // Build SDK config
-        let config = aws_config::defaults(aws_config::BehaviorVersion::latest())
+        // Build SDK config loader
+        let mut config_loader = aws_config::defaults(aws_config::BehaviorVersion::latest())
             .credentials_provider(credentials)
             .region(aws_config::Region::new(region))
-            .endpoint_url(&endpoint)
-            .load()
-            .await;
+            .endpoint_url(&endpoint);
+
+        // When insecure mode is enabled or a custom CA bundle is provided, use the reqwest
+        // connector which supports danger_accept_invalid_certs and custom root certificates.
+        if alias.insecure || alias.ca_bundle.is_some() {
+            let connector =
+                ReqwestConnector::new(alias.insecure, alias.ca_bundle.as_deref()).await?;
+            config_loader = config_loader.http_client(connector);
+        }
+
+        let config = config_loader.load().await;
 
         // Build S3 client with path-style addressing for compatibility
         let s3_config = aws_sdk_s3::config::Builder::from(&config)
@@ -736,4 +884,29 @@ mod tests {
         assert_eq!(info.key, "test.txt");
         assert_eq!(info.size_bytes, Some(1024));
     }
+
+    #[tokio::test]
+    async fn reqwest_connector_insecure_without_ca_bundle_succeeds() {
+        // When insecure is true and no CA bundle is provided, the connector should be created.
+        let connector = ReqwestConnector::new(true, None).await;
+        assert!(
+            connector.is_ok(),
+            "Expected insecure connector creation to succeed"
+        );
+    }
+
+    #[tokio::test]
+    async fn reqwest_connector_invalid_ca_bundle_path_surfaces_error() {
+        // Use an obviously invalid path (empty string) to trigger a read error.
+        let result = ReqwestConnector::new(false, Some("")).await;
+        match result {
+            Err(Error::Network(msg)) => {
+                assert!(
+                    msg.contains("Failed to read CA bundle"),
+                    "Unexpected error message: {msg}"
+                );
+            }
+            other => panic!("Expected Error::Network for invalid path, got: {:?}", other),
+        }
+    }
 }