diff --git a/libs/pageserver_api/src/models.rs b/libs/pageserver_api/src/models.rs
index 6abdcb88d0fb..231a604b475b 100644
--- a/libs/pageserver_api/src/models.rs
+++ b/libs/pageserver_api/src/models.rs
@@ -651,6 +651,17 @@ pub struct TenantDetails {
     pub timelines: Vec<TimelineId>,
 }
 
+#[derive(Serialize, Deserialize, PartialEq, Eq, Clone, Copy, Debug)]
+pub enum TimelineArchivalState {
+    Archived,
+    Unarchived,
+}
+
+#[derive(Serialize, Deserialize, PartialEq, Eq, Clone)]
+pub struct TimelineArchivalConfigRequest {
+    pub state: TimelineArchivalState,
+}
+
 /// This represents the output of the "timeline_detail" and "timeline_list" API calls.
 #[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct TimelineInfo {
diff --git a/pageserver/src/http/openapi_spec.yml b/pageserver/src/http/openapi_spec.yml
index 4d243ddeb995..087d281a0c7b 100644
--- a/pageserver/src/http/openapi_spec.yml
+++ b/pageserver/src/http/openapi_spec.yml
@@ -397,6 +397,51 @@ paths:
         "202":
           description: Tenant scheduled to load successfully
 
+  /v1/tenant/{tenant_shard_id}/timeline/{timeline_id}/archival_config:
+    parameters:
+      - name: tenant_shard_id
+        in: path
+        required: true
+        schema:
+          type: string
+      - name: timeline_id
+        in: path
+        required: true
+        schema:
+          type: string
+    put:
+      description: |
+        Either archives or unarchives the given timeline.
+        An archived timeline may not have any non-archived children.
+      requestBody:
+        required: false
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/ArchivalConfigRequest"
+      responses:
+        "200":
+          description: Timeline (un)archived successfully
+        "409":
+          description: |
+            The tenant/timeline is already being modified, perhaps by a concurrent call to this API
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ConflictError"
+        "500":
+          description: Generic operation error
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        "503":
+          description: Temporarily unavailable, please retry.
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ServiceUnavailableError"
+
   /v1/tenant/{tenant_id}/synthetic_size:
     parameters:
       - name: tenant_id
@@ -846,6 +891,15 @@ components:
         warm:
           type: boolean
           description: Whether to poll remote storage for layers to download.  If false, secondary locations don't download anything.
+    ArchivalConfigRequest:
+      type: object
+      required
+        - state
+      properties:
+        state:
+          description: The archival state of a timeline
+          type: string
+          enum: ["Archived", "Unarchived"]
     TenantConfig:
       type: object
       properties:
diff --git a/pageserver/src/http/routes.rs b/pageserver/src/http/routes.rs
index d7ef70477f45..b8063eb5a26b 100644
--- a/pageserver/src/http/routes.rs
+++ b/pageserver/src/http/routes.rs
@@ -18,14 +18,17 @@ use hyper::StatusCode;
 use hyper::{Body, Request, Response, Uri};
 use metrics::launch_timestamp::LaunchTimestamp;
 use pageserver_api::models::AuxFilePolicy;
+use pageserver_api::models::DownloadRemoteLayersTaskSpawnRequest;
 use pageserver_api::models::IngestAuxFilesRequest;
 use pageserver_api::models::ListAuxFilesRequest;
 use pageserver_api::models::LocationConfig;
 use pageserver_api::models::LocationConfigListResponse;
+use pageserver_api::models::LocationConfigMode;
 use pageserver_api::models::LsnLease;
 use pageserver_api::models::LsnLeaseRequest;
 use pageserver_api::models::ShardParameters;
 use pageserver_api::models::TenantDetails;
+use pageserver_api::models::TenantLocationConfigRequest;
 use pageserver_api::models::TenantLocationConfigResponse;
 use pageserver_api::models::TenantScanRemoteStorageResponse;
 use pageserver_api::models::TenantScanRemoteStorageShard;
@@ -33,12 +36,10 @@ use pageserver_api::models::TenantShardLocation;
 use pageserver_api::models::TenantShardSplitRequest;
 use pageserver_api::models::TenantShardSplitResponse;
 use pageserver_api::models::TenantSorting;
+use pageserver_api::models::TimelineArchivalConfigRequest;
 use pageserver_api::models::TopTenantShardItem;
 use pageserver_api::models::TopTenantShardsRequest;
 use pageserver_api::models::TopTenantShardsResponse;
-use pageserver_api::models::{
-    DownloadRemoteLayersTaskSpawnRequest, LocationConfigMode, TenantLocationConfigRequest,
-};
 use pageserver_api::shard::ShardCount;
 use pageserver_api::shard::TenantShardId;
 use remote_storage::DownloadError;
@@ -664,6 +665,39 @@ async fn timeline_preserve_initdb_handler(
     json_response(StatusCode::OK, ())
 }
 
+async fn timeline_archival_config_handler(
+    mut request: Request<Body>,
+    _cancel: CancellationToken,
+) -> Result<Response<Body>, ApiError> {
+    let tenant_shard_id: TenantShardId = parse_request_param(&request, "tenant_shard_id")?;
+    let timeline_id: TimelineId = parse_request_param(&request, "timeline_id")?;
+
+    let request_data: TimelineArchivalConfigRequest = json_request(&mut request).await?;
+    check_permission(&request, Some(tenant_shard_id.tenant_id))?;
+    let state = get_state(&request);
+
+    async {
+        let tenant = state
+            .tenant_manager
+            .get_attached_tenant_shard(tenant_shard_id)?;
+
+        tenant
+            .apply_timeline_archival_config(timeline_id, request_data.state)
+            .await
+            .context("applying archival config")
+            .map_err(ApiError::InternalServerError)?;
+        Ok::<_, ApiError>(())
+    }
+    .instrument(info_span!("timeline_archival_config",
+                tenant_id = %tenant_shard_id.tenant_id,
+                shard_id = %tenant_shard_id.shard_slug(),
+                state = ?request_data.state,
+                %timeline_id))
+    .await?;
+
+    json_response(StatusCode::OK, ())
+}
+
 async fn timeline_detail_handler(
     request: Request<Body>,
     _cancel: CancellationToken,
@@ -2789,6 +2823,10 @@ pub fn make_router(
             "/v1/tenant/:tenant_shard_id/timeline/:timeline_id/preserve_initdb_archive",
             |r| api_handler(r, timeline_preserve_initdb_handler),
         )
+        .post(
+            "/v1/tenant/:tenant_shard_id/timeline/:timeline_id/archival_config",
+            |r| api_handler(r, timeline_archival_config_handler),
+        )
         .get("/v1/tenant/:tenant_shard_id/timeline/:timeline_id", |r| {
             api_handler(r, timeline_detail_handler)
         })
diff --git a/pageserver/src/tenant.rs b/pageserver/src/tenant.rs
index 637051413f16..01f7ac626bbc 100644
--- a/pageserver/src/tenant.rs
+++ b/pageserver/src/tenant.rs
@@ -21,6 +21,7 @@ use futures::FutureExt;
 use futures::StreamExt;
 use pageserver_api::models;
 use pageserver_api::models::AuxFilePolicy;
+use pageserver_api::models::TimelineArchivalState;
 use pageserver_api::models::TimelineState;
 use pageserver_api::models::TopTenantShardItem;
 use pageserver_api::models::WalRedoManagerStatus;
@@ -1228,6 +1229,14 @@ impl Tenant {
         Ok(timeline_preloads)
     }
 
+    pub async fn apply_timeline_archival_config(
+        &self,
+        _timeline_id: TimelineId,
+        _config: TimelineArchivalState,
+    ) -> anyhow::Result<()> {
+        Ok(())
+    }
+
     pub(crate) fn tenant_shard_id(&self) -> TenantShardId {
         self.tenant_shard_id
     }