StarUML Alternatives

PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.

Looking for an affordable software with Enterprise Architecture tool, PMBOK tool, UML tool, Agile tool, BPMN tool and UX tool? Read this page for details.

UMLet - Free UML Tool for Fast UML Diagrams

LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.

Modelio is an open source modeling tool supporting natively UML, BPMN and model exchange with XMI.

Online diagramming application

Dia is a GTK+ based diagram creation program for GNU/Linux, MacOS X, Unix, and Windows, and is released under the GPL license.

Simplify and communicate complex information using data-linked diagrams.

Enterprise Architect - UML Design Tools and UML CASE tools for software development | Sparx Systems

Umbrello UML Modeller is a Unified Modelling Language diagram programme for KDE.

Papyrus

yEd is a free desktop application to quickly create, import, edit, and automatically arrange diagrams. It runs on Windows, Mac OS X, and Unix/Linux.