diff --git a/src/EFCore.PG/Query/Internal/NpgsqlQueryableMethodTranslatingExpressionVisitor.cs b/src/EFCore.PG/Query/Internal/NpgsqlQueryableMethodTranslatingExpressionVisitor.cs
index ceb1f13bd..ccd5fb8ad 100644
--- a/src/EFCore.PG/Query/Internal/NpgsqlQueryableMethodTranslatingExpressionVisitor.cs
+++ b/src/EFCore.PG/Query/Internal/NpgsqlQueryableMethodTranslatingExpressionVisitor.cs
@@ -1,4 +1,5 @@
 using System.Diagnostics.CodeAnalysis;
+using Microsoft.EntityFrameworkCore.Storage.Json;
 using Npgsql.EntityFrameworkCore.PostgreSQL.Extensions.Internal;
 using Npgsql.EntityFrameworkCore.PostgreSQL.Infrastructure.Internal;
 using Npgsql.EntityFrameworkCore.PostgreSQL.Query.Expressions;
@@ -38,6 +39,10 @@ private static readonly MethodInfo ILike2MethodInfo
     private static readonly MethodInfo MatchesLQuery =
         typeof(LTree).GetRuntimeMethod(nameof(LTree.MatchesLQuery), [typeof(string)])!;
 
+    private static readonly MethodInfo JsonValueParameterSerializerMethod =
+        typeof(NpgsqlQueryableMethodTranslatingExpressionVisitor).GetTypeInfo()
+            .GetDeclaredMethod(nameof(SerializeJsonValueParameter))!;
+
     #endregion
 
     /// <summary>
@@ -788,20 +793,31 @@ ScalarSubqueryExpression subqueryExpression
                 (translatedItem, array) = _sqlExpressionFactory.ApplyTypeMappingsOnItemAndArray(translatedItem, array);
 
                 // TODO: Null semantics - need to coalesce NULL on the item side to 'null'::jsonb.
-                // TODO: For constant/parameter, use JsonValueReaderWriter to produce the JSON value client-side
+                var jsonValueReaderWriter = translatedItem.TypeMapping?.JsonValueReaderWriter;
+                var jsonbTypeMapping = _typeMappingSource.FindMapping("jsonb")!;
+                SqlExpression jsonValue = translatedItem switch
+                {
+                    SqlParameterExpression parameter when jsonValueReaderWriter is not null
+                        => CreateJsonValueParameter(parameter, jsonValueReaderWriter, jsonbTypeMapping),
+
+                    SqlConstantExpression { Value: not null } constant when jsonValueReaderWriter is not null
+                        => _sqlExpressionFactory.Constant(
+                            jsonValueReaderWriter.ToJsonString(constant.Value), jsonbTypeMapping),
+
+                    _ => _sqlExpressionFactory.Function(
+                        "to_jsonb",
+                        [translatedItem is SqlConstantExpression { Value: string }
+                            ? _sqlExpressionFactory.Convert(translatedItem, typeof(string), _typeMappingSource.FindMapping(typeof(string)))
+                            : translatedItem],
+                        nullable: true,
+                        argumentsPropagateNullability: TrueArrays[1],
+                        typeof(string),
+                        jsonbTypeMapping)
+                };
+
                 return BuildSimplifiedShapedQuery(
                     source,
-                    _sqlExpressionFactory.Contains(
-                        array,
-                        _sqlExpressionFactory.Function(
-                            "to_jsonb",
-                            [translatedItem is SqlConstantExpression { Value: string }
-                                ? _sqlExpressionFactory.Convert(translatedItem, typeof(string), _typeMappingSource.FindMapping(typeof(string)))
-                                : translatedItem],
-                            nullable: true,
-                            argumentsPropagateNullability: TrueArrays[1],
-                            typeof(string),
-                            _typeMappingSource.FindMapping("jsonb"))));
+                    _sqlExpressionFactory.Contains(array, jsonValue));
             }
         }
 
@@ -867,6 +883,34 @@ ScalarSubqueryExpression subqueryExpression
         return base.TranslateCount(source, predicate);
     }
 
+    private SqlParameterExpression CreateJsonValueParameter(
+        SqlParameterExpression parameter,
+        JsonValueReaderWriter jsonValueReaderWriter,
+        RelationalTypeMapping jsonbTypeMapping)
+    {
+        var runtimeParameter = _queryCompilationContext.RegisterRuntimeParameter(
+            $"__npgsql_json_contains_{parameter.Name}",
+            Expression.Lambda(
+                Expression.Call(
+                    JsonValueParameterSerializerMethod,
+                    QueryCompilationContext.QueryContextParameter,
+                    Expression.Constant(parameter.Name),
+                    Expression.Constant(jsonValueReaderWriter, typeof(JsonValueReaderWriter))),
+                QueryCompilationContext.QueryContextParameter));
+
+        return new SqlParameterExpression(runtimeParameter.Name!, typeof(string), jsonbTypeMapping);
+    }
+
+    private static string? SerializeJsonValueParameter(
+        QueryContext queryContext,
+        string parameterName,
+        JsonValueReaderWriter jsonValueReaderWriter)
+    {
+        var value = queryContext.Parameters[parameterName];
+
+        return value is null ? null : jsonValueReaderWriter.ToJsonString(value);
+    }
+
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
     ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
diff --git a/test/EFCore.PG.FunctionalTests/Query/AdHocJsonQueryNpgsqlTest.cs b/test/EFCore.PG.FunctionalTests/Query/AdHocJsonQueryNpgsqlTest.cs
index 735ce4789..eb77a2764 100644
--- a/test/EFCore.PG.FunctionalTests/Query/AdHocJsonQueryNpgsqlTest.cs
+++ b/test/EFCore.PG.FunctionalTests/Query/AdHocJsonQueryNpgsqlTest.cs
@@ -76,6 +76,52 @@ LIMIT 2
         }
     }
 
+    [ConditionalTheory, MemberData(nameof(IsAsyncData))]
+    public async Task Json_primitive_collection_contains_temporal_values(bool async)
+    {
+        var dateTime = new DateTime(2026, 1, 1, 10, 0, 0, DateTimeKind.Utc);
+        var timeOnly = new TimeOnly(10, 0);
+
+        var contextFactory = await InitializeNonSharedTest<TemporalJsonDbContext>(
+            seed: async context =>
+            {
+                context.Rows.Add(
+                    new TemporalJsonEntity
+                    {
+                        Document = new TemporalJsonDocument
+                        {
+                            Dates = [dateTime],
+                            Times = [timeOnly]
+                        }
+                    });
+                await context.SaveChangesAsync();
+            });
+
+        await using var queryContext = contextFactory.CreateDbContext();
+
+        var dateTimeCount = async
+            ? await queryContext.Rows.CountAsync(e => e.Document.Dates.Contains(dateTime))
+            : queryContext.Rows.Count(e => e.Document.Dates.Contains(dateTime));
+        var timeOnlyCount = async
+            ? await queryContext.Rows.CountAsync(e => e.Document.Times.Contains(timeOnly))
+            : queryContext.Rows.Count(e => e.Document.Times.Contains(timeOnly));
+
+        Assert.Equal(1, dateTimeCount);
+        Assert.Equal(1, timeOnlyCount);
+
+        AssertSql(
+            """
+SELECT count(*)::int
+FROM "Rows" AS r
+WHERE (r."Document" -> 'Dates') @> @__npgsql_json_contains_dateTime
+""",
+            """
+SELECT count(*)::int
+FROM "Rows" AS r
+WHERE (r."Document" -> 'Times') @> @__npgsql_json_contains_timeOnly
+""");
+    }
+
     protected class TypesDbContext(DbContextOptions options) : DbContext(options)
     {
         public DbSet<TypesContainerEntity> Entities { get; set; }
@@ -96,6 +142,26 @@ public class TypesJsonEntity
         public TimeSpan Interval { get; set; }
     }
 
+    protected class TemporalJsonDbContext(DbContextOptions options) : DbContext(options)
+    {
+        public DbSet<TemporalJsonEntity> Rows { get; set; }
+
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+            => modelBuilder.Entity<TemporalJsonEntity>().ComplexProperty(e => e.Document, d => d.ToJson());
+    }
+
+    public class TemporalJsonEntity
+    {
+        public int Id { get; set; }
+        public TemporalJsonDocument Document { get; set; }
+    }
+
+    public class TemporalJsonDocument
+    {
+        public List<DateTime> Dates { get; set; }
+        public List<TimeOnly> Times { get; set; }
+    }
+
     protected void AssertSql(params string[] expected)
         => ((TestSqlLoggerFactory)ListLoggerFactory).AssertBaseline(expected);
 }