diff --git a/tests/AVEVA.Historian.Client.Tests/HistorianSessionRoundTripTests.cs b/tests/AVEVA.Historian.Client.Tests/HistorianSessionRoundTripTests.cs
new file mode 100644
index 0000000..1cfce4d
--- /dev/null
+++ b/tests/AVEVA.Historian.Client.Tests/HistorianSessionRoundTripTests.cs
@@ -0,0 +1,88 @@
+using AVEVA.Historian.Client.Models;
+using Xunit.Abstractions;
+
+namespace AVEVA.Historian.Client.Tests;
+
+/// <summary>
+/// Live end-to-end round-trip for <see cref="HistorianSession"/>: open → write → read → status →
+/// ping → dispose — ALL on ONE reused session (no re-handshake). Env-gated exactly like
+/// <see cref="HandshakeReuseSpikeTests"/> (silent skip without HISTORIAN_GRPC_HOST +
+/// HISTORIAN_WRITE_SANDBOX_TAG + HISTORIAN_USER). Bounded write to the sandbox tag only.
+/// </summary>
+public sealed class HistorianSessionRoundTripTests
+{
+    private readonly ITestOutputHelper _output;
+
+    public HistorianSessionRoundTripTests(ITestOutputHelper output) => _output = output;
+
+    [Fact]
+    public async Task Session_WriteReadStatusPing_AllOnOneSession()
+    {
+        string? host = Environment.GetEnvironmentVariable("HISTORIAN_GRPC_HOST");
+        string? sandboxTag = Environment.GetEnvironmentVariable("HISTORIAN_WRITE_SANDBOX_TAG");
+        if (string.IsNullOrWhiteSpace(host) || string.IsNullOrWhiteSpace(sandboxTag)
+            || string.IsNullOrEmpty(Environment.GetEnvironmentVariable("HISTORIAN_USER")))
+        {
+            return; // skip — env not configured
+        }
+
+        HistorianClientOptions options = BuildOptions(host);
+        await using var client = new HistorianClient(options);
+        await using HistorianSession session = await client.OpenSessionAsync(HistorianSessionKind.WriteEnabled, CancellationToken.None);
+
+        // 1) write on the session
+        bool wrote = await session.AddHistoricalValuesAsync(sandboxTag,
+            new[] { new HistorianHistoricalValue(DateTime.UtcNow, 42.0, OpcQuality: 192) },
+            CancellationToken.None);
+        Assert.True(wrote);
+        _output.WriteLine("1) write -> ok");
+
+        // 2) read on the SAME session
+        DateTime end = DateTime.UtcNow, start = end - TimeSpan.FromDays(7);
+        var rows = new List<HistorianSample>();
+        await foreach (HistorianSample s in session.ReadRawAsync(sandboxTag, start, end, 8, CancellationToken.None))
+            rows.Add(s);
+        _output.WriteLine($"2) session read rows={rows.Count}");
+        Assert.NotEmpty(rows);
+
+        // 3) status + ping on the SAME session
+        string? version = await session.GetSystemParameterAsync("HistorianVersion", CancellationToken.None);
+        Assert.False(string.IsNullOrWhiteSpace(version));
+        _output.WriteLine($"3) HistorianVersion={version}");
+
+        await session.PingAsync(CancellationToken.None); // must not throw
+        _output.WriteLine("4) ping -> ok");
+
+        _output.WriteLine("session round-trip OK (write+read+status+ping on one session)");
+    }
+
+    // verbatim copy of BuildOptions from HandshakeReuseSpikeTests
+    private static HistorianClientOptions BuildOptions(string host)
+    {
+        string? user = Environment.GetEnvironmentVariable("HISTORIAN_USER");
+        string? password = Environment.GetEnvironmentVariable("HISTORIAN_PASSWORD");
+        bool explicitCreds = !string.IsNullOrEmpty(user);
+        int port = int.TryParse(Environment.GetEnvironmentVariable("HISTORIAN_GRPC_PORT"), out int parsed)
+            ? parsed
+            : HistorianClientOptions.DefaultGrpcPort;
+        bool tls = string.Equals(Environment.GetEnvironmentVariable("HISTORIAN_GRPC_TLS"), "true", StringComparison.OrdinalIgnoreCase);
+        TimeSpan timeout = int.TryParse(Environment.GetEnvironmentVariable("HISTORIAN_GRPC_TIMEOUT"), out int secs) && secs > 0
+            ? TimeSpan.FromSeconds(secs)
+            : new HistorianClientOptions { Host = host }.RequestTimeout;
+
+        return new HistorianClientOptions
+        {
+            Host = host,
+            Port = port,
+            Transport = HistorianTransport.RemoteGrpc,
+            GrpcUseTls = tls,
+            AllowUntrustedServerCertificate = tls,
+            ServerDnsIdentity = Environment.GetEnvironmentVariable("HISTORIAN_GRPC_DNSID"),
+            IntegratedSecurity = !explicitCreds,
+            UserName = user ?? string.Empty,
+            Password = password ?? string.Empty,
+            RequestTimeout = timeout,
+            Compression = true
+        };
+    }
+}