diff --git a/sequencing-server/src/lib/batchLoaders/simulatedActivityBatchLoader.ts b/sequencing-server/src/lib/batchLoaders/simulatedActivityBatchLoader.ts
index 074b7258d5..0e0462ba3f 100644
--- a/sequencing-server/src/lib/batchLoaders/simulatedActivityBatchLoader.ts
+++ b/sequencing-server/src/lib/batchLoaders/simulatedActivityBatchLoader.ts
@@ -14,29 +14,41 @@ export const simulatedActivitiesBatchLoader: BatchLoader<
   const result = await opts.graphqlClient.batchRequests<
     {
       data: {
-        simulated_activity: GraphQLSimulatedActivityInstance[];
+        simulation_dataset: {
+          id: number;
+          simulation: {
+            plan: {
+              id: number;
+              model_id: number;
+            };
+          };
+          simulation_start_time: string;
+          dataset: { spans: GQLSpan[] };
+        };
       };
     }[]
   >(
     keys.map(key => ({
       document: gql`
         query ($simulationDatasetId: Int!) {
-          simulated_activity(where: { simulation_dataset_id: { _eq: $simulationDatasetId } }) {
+          simulation_dataset: simulation_dataset_by_pk(id: $simulationDatasetId) {
             id
-            simulation_dataset {
-              id
-              simulation {
-                plan {
-                  model_id
-                }
+            simulation {
+              plan {
+                model_id
+                id
+              }
+            }
+            simulation_start_time
+            dataset {
+              spans {
+                id
+                attributes
+                start_offset
+                duration
+                activity_type_name: type
               }
             }
-            attributes
-            start_offset
-            start_time
-            end_time
-            duration
-            activity_type_name
           }
         }
       `,
@@ -48,18 +60,33 @@ export const simulatedActivitiesBatchLoader: BatchLoader<
 
   return Promise.all(
     keys.map(async ({ simulationDatasetId }) => {
-      const simulatedActivities = result.find(
-        res => res.data.simulated_activity[0]?.simulation_dataset.id === simulationDatasetId,
-      )?.data.simulated_activity;
-      if (simulatedActivities === undefined) {
+      const simulation_dataset = result.find(res => res.data.simulation_dataset.id === simulationDatasetId)?.data
+        .simulation_dataset;
+      if (simulation_dataset === undefined) {
         return new ErrorWithStatusCode(`No simulation_dataset with id: ${simulationDatasetId}`, 404);
       }
+
+      const spans = simulation_dataset.dataset.spans;
+
+      const simulatedActivities: GraphQLSimulatedActivityInstance[] = spans.map(span => {
+        return {
+          id: span.id,
+          simulation_dataset_id: simulation_dataset.id,
+          plan_id: simulation_dataset.simulation.plan.id,
+          model_id: simulation_dataset.simulation.plan.model_id,
+          attributes: span.attributes,
+          duration: span.duration,
+          start_offset: span.start_offset,
+          simulation_start_time: simulation_dataset.simulation_start_time,
+          activity_type_name: span.activity_type_name,
+        };
+      });
       return Promise.all(
         simulatedActivities.map(async simulatedActivity =>
           mapGraphQLActivityInstance(
             simulatedActivity,
             await opts.activitySchemaDataLoader.load({
-              missionModelId: simulatedActivity.simulation_dataset.simulation.plan.model_id,
+              missionModelId: simulation_dataset.simulation.plan.model_id,
               activityTypeName: simulatedActivity.activity_type_name,
             }),
           ),
@@ -77,32 +104,41 @@ export const simulatedActivityInstanceBySimulatedActivityIdBatchLoader: BatchLoa
   const result = await opts.graphqlClient.batchRequests<
     {
       data: {
-        simulated_activity: GraphQLSimulatedActivityInstance[];
+        simulation_dataset: {
+          id: number;
+          simulation_start_time: string;
+          simulation: {
+            plan: {
+              id: number;
+              model_id: number;
+            };
+          };
+          dataset: { spans: GQLSpan[] };
+        };
       };
     }[]
   >(
     keys.map(key => ({
       document: gql`
         query ($simulationDatasetId: Int!, $simulatedActivityId: Int!) {
-          simulated_activity(
-            where: { simulation_dataset_id: { _eq: $simulationDatasetId }, id: { _eq: $simulatedActivityId } }
-          ) {
+          simulation_dataset: simulation_dataset_by_pk(id: $simulationDatasetId) {
             id
-            simulation_dataset {
-              id
-              simulation {
-                plan {
-                  model_id
-                }
-                plan_id
+            simulation_start_time
+            simulation {
+              plan {
+                id
+                model_id
+              }
+            }
+            dataset {
+              spans: spans(where: { id: { _eq: $simulatedActivityId } }) {
+                id
+                attributes
+                start_offset
+                duration
+                activity_type_name: type
               }
             }
-            attributes
-            start_offset
-            start_time
-            end_time
-            duration
-            activity_type_name
           }
         }
       `,
@@ -115,21 +151,44 @@ export const simulatedActivityInstanceBySimulatedActivityIdBatchLoader: BatchLoa
 
   return Promise.all(
     keys.map(async ({ simulationDatasetId, simulatedActivityId }) => {
-      const simulatedActivity = result.find(
-        res =>
-          res.data.simulated_activity[0]?.simulation_dataset.id === simulationDatasetId &&
-          res.data.simulated_activity[0]?.id === simulatedActivityId,
-      )?.data.simulated_activity[0];
-      if (simulatedActivity === undefined) {
+      const simulation_dataset = result.find(res =>
+        res.data?.simulation_dataset?.dataset?.spans?.some(span => span.id === simulatedActivityId),
+      )?.data.simulation_dataset;
+      if (simulation_dataset === undefined) {
+        return new ErrorWithStatusCode(`No simulation_dataset with id: ${simulationDatasetId}`, 404);
+      }
+
+      const spans = simulation_dataset?.dataset.spans;
+      if (spans === undefined || spans.length === 0 || spans[0] === undefined) {
         return new ErrorWithStatusCode(
           `No simulation_dataset with id: ${simulationDatasetId} and simulated activity id: ${simulatedActivityId}`,
           404,
         );
       }
+
+      if(spans.length > 1) {
+        return new ErrorWithStatusCode(
+            `Too many spans with simulated activity id ${simulatedActivityId} found for simulation_dataset with id ${simulationDatasetId}`,
+            404,
+        );
+      }
+
+      const span = spans[0];
+      const simulatedActivity: GraphQLSimulatedActivityInstance = {
+        id: span.id,
+        simulation_dataset_id: simulation_dataset.id,
+        plan_id: simulation_dataset.simulation.plan.id,
+        model_id: simulation_dataset.simulation.plan.model_id,
+        attributes: span.attributes,
+        duration: span.duration,
+        start_offset: span.start_offset,
+        simulation_start_time: simulation_dataset.simulation_start_time,
+        activity_type_name: span.activity_type_name,
+      };
       return mapGraphQLActivityInstance(
         simulatedActivity,
         await opts.activitySchemaDataLoader.load({
-          missionModelId: simulatedActivity.simulation_dataset.simulation.plan.model_id,
+          missionModelId: simulation_dataset.simulation.plan.model_id,
           activityTypeName: simulatedActivity.activity_type_name,
         }),
       );
@@ -173,25 +232,29 @@ export interface SimulatedActivity<
   activityTypeName: string;
 }
 
+export interface GQLSpan<
+  ActivityArguments extends Record<string, unknown> = Record<string, unknown>,
+  ActivityComputedAttributes extends Record<string, unknown> = Record<string, unknown>,
+> {
+  id: number;
+  attributes: GraphQLSimulatedActivityAttributes<ActivityArguments, ActivityComputedAttributes>;
+  start_offset: string;
+  duration: string;
+  activity_type_name: string;
+}
+
 export interface GraphQLSimulatedActivityInstance<
   ActivityArguments extends Record<string, unknown> = Record<string, unknown>,
   ActivityComputedAttributes extends Record<string, unknown> = Record<string, unknown>,
 > {
   id: number;
-  simulation_dataset: {
-    id: number;
-    simulation: {
-      plan: {
-        model_id: number;
-      };
-      plan_id: number;
-    };
-  };
+  simulation_dataset_id: number;
+  plan_id: number;
+  model_id: number;
   attributes: GraphQLSimulatedActivityAttributes<ActivityArguments, ActivityComputedAttributes>;
   duration: string;
   start_offset: string;
-  start_time: string;
-  end_time: string;
+  simulation_start_time: string;
   activity_type_name: string;
 }
 
@@ -199,18 +262,28 @@ export function mapGraphQLActivityInstance(
   activityInstance: GraphQLSimulatedActivityInstance<any, any>,
   activitySchema: GraphQLActivitySchema,
 ): SimulatedActivity {
+  const duration = activityInstance.duration
+    ? Temporal.Duration.from(parse(activityInstance.duration).toISOString())
+    : null;
+  const startOffset: Temporal.Duration = Temporal.Duration.from(parse(activityInstance.start_offset).toISOString());
+  const startTime: Temporal.Instant = Temporal.Instant.from(activityInstance.simulation_start_time)
+    .toZonedDateTimeISO('UTC')
+    .add(startOffset)
+    .toInstant();
+  const endTime = duration ? startTime.toZonedDateTimeISO('UTC').add(duration).toInstant() : null;
+
   return {
     simulationDataset: {
       simulation: {
-        planId: activityInstance.simulation_dataset.simulation.plan_id,
+        planId: activityInstance.plan_id,
       },
     },
     id: activityInstance.id,
-    duration: activityInstance.duration ? Temporal.Duration.from(parse(activityInstance.duration).toISOString()) : null,
-    startOffset: Temporal.Duration.from(parse(activityInstance.start_offset).toISOString()),
-    startTime: Temporal.Instant.from(activityInstance.start_time),
-    endTime: activityInstance.end_time ? Temporal.Instant.from(activityInstance.end_time) : null,
-    simulationDatasetId: activityInstance.simulation_dataset.id,
+    duration,
+    startOffset,
+    startTime,
+    endTime,
+    simulationDatasetId: activityInstance.simulation_dataset_id,
     activityTypeName: activityInstance.activity_type_name,
     attributes: {
       arguments: Object.entries(activityInstance.attributes.arguments).reduce((acc, [key, value]) => {
@@ -219,7 +292,7 @@ export function mapGraphQLActivityInstance(
           acc[key] = convertType(value, param.schema);
         }
         return acc;
-      }, {} as { [attributeName: string]: any }),
+      }, {} as Record<string, any>),
       directiveId: activityInstance.attributes.directiveId,
       computed: activityInstance.attributes.computedAttributes
         ? convertType(activityInstance.attributes.computedAttributes, activitySchema.computed_attributes_value_schema)
diff --git a/sequencing-server/src/routes/seqjson.ts b/sequencing-server/src/routes/seqjson.ts
index 14a3fc2b40..3aeedd93f2 100644
--- a/sequencing-server/src/routes/seqjson.ts
+++ b/sequencing-server/src/routes/seqjson.ts
@@ -137,25 +137,22 @@ seqjsonRouter.post('/get-seqjson-for-seqid-and-simulation-dataset', async (req,
       errors: ReturnType<UserCodeError['toJSON']>[] | null;
     }>(
       `
-        with joined_table as (select activity_instance_commands.commands,
-                                      activity_instance_commands.activity_instance_id,
-                                      activity_instance_commands.errors,
-                                      activity_instance_commands.expansion_run_id
-                              from sequence
-                                      join sequence_to_simulated_activity
-                                          on sequence.seq_id = sequence_to_simulated_activity.seq_id and
-                                              sequence.simulation_dataset_id =
-                                              sequence_to_simulated_activity.simulation_dataset_id
-                                      join activity_instance_commands
-                                          on sequence_to_simulated_activity.simulated_activity_id =
-                                              activity_instance_commands.activity_instance_id
-                                      join expansion_run
-                                          on activity_instance_commands.expansion_run_id = expansion_run.id
-                              where sequence.seq_id = $2
-                                and sequence.simulation_dataset_id = $1),
-              max_values as (select activity_instance_id, max(expansion_run_id) as max_expansion_run_id
-                            from joined_table
-                            group by activity_instance_id)
+        with joined_table as (
+          select  aic.commands,
+                  aic.activity_instance_id,
+                  aic.errors,
+                  aic.expansion_run_id
+          from sequence_to_simulated_activity ssa
+          join activity_instance_commands aic
+            on ssa.simulated_activity_id = aic.activity_instance_id
+          where (ssa.simulation_dataset_id, ssa.seq_id) = ($1, $2)),
+          max_values as (
+            select
+              activity_instance_id,
+              max(expansion_run_id) as max_expansion_run_id
+            from joined_table
+            group by activity_instance_id
+          )
         select joined_table.commands,
                 joined_table.activity_instance_id,
                 joined_table.errors
@@ -283,23 +280,16 @@ seqjsonRouter.post('/bulk-get-seqjson-for-seqid-and-simulation-dataset', async (
         with
         joined_table as (
           select
-            activity_instance_commands.commands,
-            activity_instance_commands.activity_instance_id,
-            activity_instance_commands.errors,
-            activity_instance_commands.expansion_run_id,
-            sequence.seq_id,
-            sequence.simulation_dataset_id
-          from sequence
-            join sequence_to_simulated_activity
-              on sequence.seq_id = sequence_to_simulated_activity.seq_id
-                and sequence.simulation_dataset_id =
-                  sequence_to_simulated_activity.simulation_dataset_id
-            join activity_instance_commands
-              on sequence_to_simulated_activity.simulated_activity_id =
-                activity_instance_commands.activity_instance_id
-            join expansion_run
-              on activity_instance_commands.expansion_run_id = expansion_run.id
-          where (sequence.seq_id, sequence.simulation_dataset_id) in (${pgFormat('%L', inputTuples)})
+            aic.commands,
+            aic.activity_instance_id,
+            aic.errors,
+            aic.expansion_run_id,
+            ssa.seq_id,
+            ssa.simulation_dataset_id
+          from sequence_to_simulated_activity ssa
+          join activity_instance_commands aic
+            on ssa.simulated_activity_id = aic.activity_instance_id
+          where (ssa.seq_id, ssa.simulation_dataset_id) in (${pgFormat('%L', inputTuples)})
         ),
         max_values as (
           select
@@ -328,8 +318,8 @@ seqjsonRouter.post('/bulk-get-seqjson-for-seqid-and-simulation-dataset', async (
     }>(
       `
         select metadata, seq_id, simulation_dataset_id
-        from sequence
-        where (sequence.seq_id, sequence.simulation_dataset_id) in (${pgFormat('%L', inputTuples)});
+        from sequence s
+        where (s.seq_id, s.simulation_dataset_id) in (${pgFormat('%L', inputTuples)});
       `,
     ),
   ]);