diff --git a/services/blob/src/s3.rs b/services/blob/src/s3.rs
--- a/services/blob/src/s3.rs
+++ b/services/blob/src/s3.rs
@@ -1,6 +1,10 @@
 use anyhow::{anyhow, Result};
-use aws_sdk_s3::model::CompletedPart;
 use aws_sdk_s3::Client as S3Client;
+use aws_sdk_s3::{
+  model::{CompletedMultipartUpload, CompletedPart},
+  output::CreateMultipartUploadOutput,
+  types::ByteStream,
+};
 use std::sync::Arc;
 
 /// A helper structure representing an S3 object path
@@ -49,17 +53,66 @@
 impl MultiPartUploadSession {
   /// Starts a new upload session and returns its instance
   pub async fn start(client: &Arc<S3Client>, s3_path: &S3Path) -> Result<Self> {
-    unimplemented!()
+    let multipart_upload_res: CreateMultipartUploadOutput = client
+      .create_multipart_upload()
+      .bucket(&s3_path.bucket_name)
+      .key(&s3_path.object_name)
+      .send()
+      .await?;
+
+    let upload_id = multipart_upload_res
+      .upload_id()
+      .ok_or(anyhow!("Upload ID expected to be present"))?;
+
+    Ok(MultiPartUploadSession {
+      client: client.clone(),
+      bucket_name: String::from(&s3_path.bucket_name),
+      object_name: String::from(&s3_path.object_name),
+      upload_id: String::from(upload_id),
+      upload_parts: Vec::new(),
+    })
   }
 
   /// adds data part to the multipart upload
   pub async fn add_part(&mut self, part: Vec<u8>) -> Result<()> {
-    unimplemented!()
+    let stream = ByteStream::from(part);
+    let part_number: i32 = self.upload_parts.len() as i32 + 1;
+    let upload_result = self
+      .client
+      .upload_part()
+      .key(&self.object_name)
+      .bucket(&self.bucket_name)
+      .upload_id(&self.upload_id)
+      .part_number(part_number)
+      .body(stream)
+      .send()
+      .await?;
+
+    let completed_part = CompletedPart::builder()
+      .e_tag(upload_result.e_tag.unwrap_or_default())
+      .part_number(part_number)
+      .build();
+    self.upload_parts.push(completed_part);
+    Ok(())
   }
 
   /// finishes the upload
   pub async fn finish_upload(&self) -> Result<()> {
-    unimplemented!()
+    let completed_multipart_upload = CompletedMultipartUpload::builder()
+      .set_parts(Some(self.upload_parts.clone()))
+      .build();
+
+    self
+      .client
+      .complete_multipart_upload()
+      .bucket(&self.bucket_name)
+      .key(&self.object_name)
+      .multipart_upload(completed_multipart_upload)
+      .upload_id(&self.upload_id)
+      .send()
+      .await?;
+
+    Ok(())
   }
 }